{"id":"CVE-2026-55174","title":"UltrafastSecp256k1 is a high-performance, multi-backend secp256k1 engine with reproducible audit evidence, compatibility shims, and profile-based review scopes","summary":"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 ver…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","cwe":["CWE-345","CWE-347"],"vendor":"shrec","product":"UltrafastSecp256k1","affected":["UltrafastSecp256k1 < 4.2.0"],"published":"2026-09-30","updated":"2026-09-30","sourceUpdated":"2026-09-30T20:17:33.243","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55174","references":[{"url":"https://github.com/shrec/UltrafastSecp256k1/commit/5478ef566c6af91b48a45c0c61f161f5b1071981","label":"security-advisories@github.com"},{"url":"https://github.com/shrec/UltrafastSecp256k1/releases/tag/v4.2.0","label":"security-advisories@github.com"},{"url":"https://github.com/shrec/UltrafastSecp256k1/releases/tag/v4.2.1","label":"security-advisories@github.com"},{"url":"https://github.com/shrec/UltrafastSecp256k1/security/advisories/GHSA-c7q2-gv3g-rgxm","label":"security-advisories@github.com"},{"url":"https://github.com/shrec/UltrafastSecp256k1/security/advisories/GHSA-c7q2-gv3g-rgxm","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-30T19:51:52.522461Z"},"ingestedAt":"2026-09-30T16:10:07.653Z","epss":0.0015,"epssPercentile":0.04125,"slug":"CVE-2026-55174","body":"## Overview\n\nUltrafastSecp256k1 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":44,"depthScoreParts":{"impact":32.5,"likelihood":0,"exploitation":12,"ransomware":0},"changes":[{"seq":213956,"id":"CVE-2026-55174","ts":1790799889952,"field":"exploit_available","old":"false","new":"true"}]}