{"id":"CVE-2024-26149","aliases":["EUVD-2024-0180","GHSA-9p8r-4xp4-gw5w","PYSEC-2024-164"],"status":"published","title":"Vyper _abi_decode Memory Overflow","description":"Vyper is a pythonic Smart Contract Language for the ethereum virtual machine. If an excessively large value is specified as the starting index for an array in `_abi_decode`, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to exploitations in contracts that use arrays within `_abi_decode`. This vulnerability affects 0.3.10 and earlier versions.","severity":{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00542,"percentile":0.45914,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-119","CWE-120"],"published":"2024-02-26T20:11:07Z","modified":"2026-10-28T02:30:21Z","fixes":[{"ecosystem":"PyPI","package":"vyper","fixed_in":["0.4.0","0.4.0b1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"vyper","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"vyper","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.0"}]}],"versions":["0.1.0b1","0.1.0b10","0.1.0b11","0.1.0b12","0.1.0b13","0.1.0b14","0.1.0b15","0.1.0b16","0.1.0b17","0.1.0b2","0.1.0b3","0.1.0b4","0.1.0b5","0.1.0b6","0.1.0b7","0.1.0b8","0.1.0b9","0.2.1","0.2.10","0.2.11","0.2.12","0.2.13","0.2.14","0.2.15","0.2.16","0.2.2","0.2.3","0.2.4","0.2.5","0.2.6","0.2.7","0.2.8","0.2.9","0.3.0","0.3.1","0.3.10","0.3.10rc1","0.3.10rc2","0.3.10rc3","0.3.10rc4","0.3.10rc5","0.3.2","0.3.3","0.3.4","0.3.5","0.3.6","0.3.7","0.3.8","0.3.9","0.4.0b1","0.4.0b2","0.4.0b3","0.4.0b4","0.4.0b5","0.4.0b6","0.4.0rc1","0.4.0rc2","0.4.0rc3","0.4.0rc4","0.4.0rc5","0.4.0rc6"]},{"source":"osv","ecosystem":"PyPI","package":"vyper","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.0b1"}]}],"versions":["0.1.0b1","0.1.0b10","0.1.0b11","0.1.0b12","0.1.0b13","0.1.0b14","0.1.0b15","0.1.0b16","0.1.0b17","0.1.0b2","0.1.0b3","0.1.0b4","0.1.0b5","0.1.0b6","0.1.0b7","0.1.0b8","0.1.0b9","0.2.1","0.2.10","0.2.11","0.2.12","0.2.13","0.2.14","0.2.15","0.2.16","0.2.2","0.2.3","0.2.4","0.2.5","0.2.6","0.2.7","0.2.8","0.2.9","0.3.0","0.3.1","0.3.10","0.3.10rc1","0.3.10rc2","0.3.10rc3","0.3.10rc4","0.3.10rc5","0.3.2","0.3.3","0.3.4","0.3.5","0.3.6","0.3.7","0.3.8","0.3.9"]}],"products":[{"vendor":"vyperlang","product":"vyper"}],"references":[{"url":"https://github.com/vyperlang/vyper/security/advisories/GHSA-9p8r-4xp4-gw5w","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Patch","Vendor Advisory","advisory","web","evidence","fix"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-26149","tags":["advisory"]},{"url":"https://github.com/vyperlang/vyper/pull/3925","tags":["web"]},{"url":"https://github.com/vyperlang/vyper/pull/4060","tags":["web"]},{"url":"https://github.com/vyperlang/vyper/pull/4091","tags":["web"]},{"url":"https://github.com/vyperlang/vyper/pull/4144","tags":["web"]},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/vyper/PYSEC-2024-164.yaml","tags":["web"]},{"url":"https://github.com/advisories/GHSA-9p8r-4xp4-gw5w","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/26xxx/CVE-2024-26149.json","tags":["advisory"]},{"url":"https://github.com/vyperlang/vyper","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2024-26149","title":"Vyper _abi_decode Memory Overflow","description":"Vyper is a pythonic Smart Contract Language for the ethereum virtual machine. If an excessively large value is specified as the starting index for an array in `_abi_decode`, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to exploitations in contracts that use arrays within `_abi_decode`. This vulnerability affects 0.3.10 and earlier versions.","status":"published","published":"2024-02-26T20:16:01.688Z","modified":"2024-08-22T20:44:05.129Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-119"],"updated_at":"2026-11-02T14:33:59.512321Z"}],"euvd":[{"id":"EUVD-2024-0180","description":"Vyper is a pythonic Smart Contract Language for the ethereum virtual machine. If an excessively large value is specified as the starting index for an array in `_abi_decode`, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to exploitations in contracts that use arrays within `_abi_decode`. This vulnerability affects 0.3.10 and earlier versions.","status":"published","published":"2024-02-26T20:16:01Z","modified":"2024-08-22T20:44:05Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-03T00:56:12.794655Z"}],"ghsa":[{"id":"GHSA-9p8r-4xp4-gw5w","title":"Vyper's `_abi_decode` vulnerable to Memory Overflow","description":"## Summary\n\nIf an excessively large value is specified as the starting index for an array in `_abi_decode`, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to bugs in contracts that use arrays within `_abi_decode`. The advisory has been assigned low severity, because it is only observable if there is a memory write between two invocations of `abi_decode` on the same input.\n\n## Proof of Concept\n\n```vyper\nevent Pwn:\n    pass\n\n@external\ndef f(x: Bytes[32 * 3]):\n    a: Bytes[32] = b\"foo\"\n    y: Bytes[32 * 3] = x\n\n    decoded_y1: Bytes[32] = _abi_decode(y, Bytes[32])\n    a = b\"bar\"\n    decoded_y2: Bytes[32] = _abi_decode(y, Bytes[32])\n\n    if decoded_y1 != decoded_y2:\n        log Pwn()\n```\n\nSending the following calldata results in `Pwn` being emitted. \n\n```\n0xd45754f8\n0000000000000000000000000000000000000000000000000000000000000020\n0000000000000000000000000000000000000000000000000000000000000060\nffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffa0\n```\n\n### Patches\nPatched in https://github.com/vyperlang/vyper/pull/3925, https://github.com/vyperlang/vyper/pull/4091, https://github.com/vyperlang/vyper/pull/4144, https://github.com/vyperlang/vyper/pull/4060.","status":"published","published":"2024-02-26T20:11:07Z","modified":"2026-03-20T05:03:23Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-119","CWE-120"],"updated_at":"2026-11-02T14:39:38.524712Z"}],"nvd":[{"id":"CVE-2024-26149","description":"Vyper is a pythonic Smart Contract Language for the ethereum virtual machine. If an excessively large value is specified as the starting index for an array in `_abi_decode`, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to exploitations in contracts that use arrays within `_abi_decode`. This vulnerability affects 0.3.10 and earlier versions.","status":"published","published":"2024-02-26T20:19:05.853Z","modified":"2026-06-17T07:17:12.147Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"secondary"},{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-119"],"updated_at":"2026-11-02T14:09:38.473056Z"}],"osv":[{"id":"CVE-2024-26149","title":"Vyper _abi_decode Memory Overflow","description":"Vyper is a pythonic Smart Contract Language for the ethereum virtual machine. If an excessively large value is specified as the starting index for an array in `_abi_decode`, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to exploitations in contracts that use arrays within `_abi_decode`. This vulnerability affects 0.3.10 and earlier versions.","status":"published","published":"2024-02-26T20:16:01.688Z","modified":"2026-10-28T02:30:21.381662866Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-119"],"updated_at":"2026-11-02T15:44:39.244433Z"},{"id":"GHSA-9p8r-4xp4-gw5w","title":"Vyper's `_abi_decode` vulnerable to Memory Overflow","description":"## Summary\n\nIf an excessively large value is specified as the starting index for an array in `_abi_decode`, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to bugs in contracts that use arrays within `_abi_decode`. The advisory has been assigned low severity, because it is only observable if there is a memory write between two invocations of `abi_decode` on the same input.\n\n## Proof of Concept\n\n```vyper\nevent Pwn:\n    pass\n\n@external\ndef f(x: Bytes[32 * 3]):\n    a: Bytes[32] = b\"foo\"\n    y: Bytes[32 * 3] = x\n\n    decoded_y1: Bytes[32] = _abi_decode(y, Bytes[32])\n    a = b\"bar\"\n    decoded_y2: Bytes[32] = _abi_decode(y, Bytes[32])\n\n    if decoded_y1 != decoded_y2:\n        log Pwn()\n```\n\nSending the following calldata results in `Pwn` being emitted. \n\n```\n0xd45754f8\n0000000000000000000000000000000000000000000000000000000000000020\n0000000000000000000000000000000000000000000000000000000000000060\nffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffa0\n```\n\n### Patches\nPatched in https://github.com/vyperlang/vyper/pull/3925, https://github.com/vyperlang/vyper/pull/4091, https://github.com/vyperlang/vyper/pull/4144, https://github.com/vyperlang/vyper/pull/4060.","status":"published","published":"2024-02-26T20:11:07Z","modified":"2026-06-10T17:14:15.814776145Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-119","CWE-120"],"updated_at":"2026-11-02T15:46:43.875515Z"},{"id":"PYSEC-2024-164","description":"Vyper is a pythonic Smart Contract Language for the ethereum virtual machine. If an excessively large value is specified as the starting index for an array in `_abi_decode`, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to exploitations in contracts that use arrays within `_abi_decode`. This vulnerability affects 0.3.10 and earlier versions.","status":"published","published":"2024-02-26T20:19:05Z","modified":"2026-06-10T17:14:18.967761542Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:52:53.837392Z"}]}}