{"id":"CVE-2026-55174","aliases":["EUVD-2026-90188","GHSA-c7q2-gv3g-rgxm"],"status":"published","title":"UltrafastSecp256k1: ECDSA adaptor verification accepts non-adaptable pre-signatures due to missing DLEQ binding","description":"UltrafastSecp256k1 is a high-performance, multi-backend secp256k1 engine with reproducible audit evidence, compatibility shims, and profile-based review scopes. Prior to version 4.2.0, UltrafastSecp256k1's ECDSA adaptor pre-signature verification accepts forged adaptor pre-signatures whose \"r\" value is not cryptographically bound to the adaptor point \"T\". This issue has been patched in version 4.2.0.","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.0015,"percentile":0.04238,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-345","CWE-347"],"published":"2026-09-30T15:49:10Z","modified":"2026-10-28T10:55:40Z","products":[{"vendor":"shrec","product":"ultrafastsecp256k1"}],"references":[{"url":"https://github.com/shrec/UltrafastSecp256k1/security/advisories/GHSA-c7q2-gv3g-rgxm","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/shrec/UltrafastSecp256k1/commit/5478ef566c6af91b48a45c0c61f161f5b1071981","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/shrec/UltrafastSecp256k1/releases/tag/v4.2.0","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/shrec/UltrafastSecp256k1/releases/tag/v4.2.1","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55174.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55174","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-55174","title":"UltrafastSecp256k1: ECDSA adaptor verification accepts non-adaptable pre-signatures due to missing DLEQ binding","description":"UltrafastSecp256k1 is a high-performance, multi-backend secp256k1 engine with reproducible audit evidence, compatibility shims, and profile-based review scopes. Prior to version 4.2.0, UltrafastSecp256k1's ECDSA adaptor pre-signature verification accepts forged adaptor pre-signatures whose \"r\" value is not cryptographically bound to the adaptor point \"T\". This issue has been patched in version 4.2.0.","status":"published","published":"2026-09-30T15:49:10.453Z","modified":"2026-09-30T19:52:01.569Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-345","CWE-347"],"updated_at":"2026-11-02T14:20:11.925815Z"}],"euvd":[{"id":"EUVD-2026-90188","description":"UltrafastSecp256k1 is a high-performance, multi-backend secp256k1 engine with reproducible audit evidence, compatibility shims, and profile-based review scopes. Prior to version 4.2.0, UltrafastSecp256k1's ECDSA adaptor pre-signature verification accepts forged adaptor pre-signatures whose \"r\" value is not cryptographically bound to the adaptor point \"T\". This issue has been patched in version 4.2.0.","status":"published","published":"2026-09-30T15:49:10Z","modified":"2026-09-30T19:52:01Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T17:27:47.293232Z"}],"nvd":[{"id":"CVE-2026-55174","description":"UltrafastSecp256k1 is a high-performance, multi-backend secp256k1 engine with reproducible audit evidence, compatibility shims, and profile-based review scopes. Prior to version 4.2.0, UltrafastSecp256k1's ECDSA adaptor pre-signature verification accepts forged adaptor pre-signatures whose \"r\" value is not cryptographically bound to the adaptor point \"T\". This issue has been patched in version 4.2.0.","status":"published","published":"2026-09-30T16:17:31.457Z","modified":"2026-09-30T20:17:33.243Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-345","CWE-347"],"updated_at":"2026-11-02T14:12:53.097633Z"}],"osv":[{"id":"CVE-2026-55174","title":"UltrafastSecp256k1: ECDSA adaptor verification accepts non-adaptable pre-signatures due to missing DLEQ binding","description":"UltrafastSecp256k1 is a high-performance, multi-backend secp256k1 engine with reproducible audit evidence, compatibility shims, and profile-based review scopes. Prior to version 4.2.0, UltrafastSecp256k1's ECDSA adaptor pre-signature verification accepts forged adaptor pre-signatures whose \"r\" value is not cryptographically bound to the adaptor point \"T\". This issue has been patched in version 4.2.0.","status":"published","published":"2026-09-30T15:49:10.453Z","modified":"2026-10-28T10:55:40.244253079Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"cwes":["CWE-345","CWE-347"],"updated_at":"2026-11-02T15:45:11.22012Z"}]}}