{"id":"CVE-2026-114615","state":"PUBLISHED","title":"Authlib incomplete algorithm-confusion fix permits HMAC forgery with prefixed public keys","description":"Authlib is a Python library which builds OAuth and OpenID Connect servers. From 1.3.1 until 1.9.0, OctKey.import_key() checks asymmetric-key markers only at byte zero while Authlib's PEM loaders accept leading whitespace, comments, or a byte-order mark. In deployments that use the documented mixed algorithm registry and already configure verification with PEM or certificate bytes containing such a prefix, an unauthenticated attacker who knows those same public-key bytes can use them as an HMAC secret and forge HS256 tokens with arbitrary identity or authorization claims. This is a bypass of the remediation for CVE-2024-37568. The module-level jwt object reaches OctKey.import_key() in authlib/jose/rfc7518/oct_key.py, where POSSIBLE_UNSAFE_KEYS fails to identify prefixed asymmetric key material. This issue is fixed in version 1.9.0.","publishedAt":"2026-10-22T21:10:02.023Z","updatedAt":"2026-10-29T02:38:05.175Z","severity":{"score":7.4,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["authlib authlib"],"affected":[{"vendor":"authlib","product":"authlib","versions":[{"version":">= 1.3.1, < 1.9.0","status":"affected"}]}],"references":["https://github.com/authlib/authlib/security/advisories/GHSA-7vr2-2fgp-9w7p","https://github.com/authlib/authlib/pull/945","https://github.com/authlib/authlib/commit/e3bd41cb29dcfee434453b135ffb487884baeedf","https://github.com/authlib/authlib/releases/tag/v1.9.0"],"weaknesses":["CWE-184","CWE-347"],"ingestedAt":"2026-10-29T20:10:43.281Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/114xxx/CVE-2026-114615.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-114615","state":"PUBLISHED","datePublished":"2026-10-22T21:10:02.023Z","dateUpdated":"2026-10-29T02:38:05.175Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-10-21T20:34:25.600Z"},"containers":{"cna":{"title":"Authlib incomplete algorithm-confusion fix permits HMAC forgery with prefixed public keys","descriptions":[{"lang":"en","value":"Authlib is a Python library which builds OAuth and OpenID Connect servers. From 1.3.1 until 1.9.0, OctKey.import_key() checks asymmetric-key markers only at byte zero while Authlib's PEM loaders accept leading whitespace, comments, or a byte-order mark. In deployments that use the documented mixed algorithm registry and already configure verification with PEM or certificate bytes containing such a prefix, an unauthenticated attacker who knows those same public-key bytes can use them as an HMAC secret and forge HS256 tokens with arbitrary identity or authorization claims. This is a bypass of the remediation for CVE-2024-37568. The module-level jwt object reaches OctKey.import_key() in authlib/jose/rfc7518/oct_key.py, where POSSIBLE_UNSAFE_KEYS fails to identify prefixed asymmetric key material. This issue is fixed in version 1.9.0."}],"affected":[{"vendor":"authlib","product":"authlib","versions":[{"version":">= 1.3.1, < 1.9.0","status":"affected"}]}],"references":[{"url":"https://github.com/authlib/authlib/security/advisories/GHSA-7vr2-2fgp-9w7p","name":"https://github.com/authlib/authlib/security/advisories/GHSA-7vr2-2fgp-9w7p","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/authlib/authlib/pull/945","name":"https://github.com/authlib/authlib/pull/945","tags":["x_refsource_MISC"]},{"url":"https://github.com/authlib/authlib/commit/e3bd41cb29dcfee434453b135ffb487884baeedf","name":"https://github.com/authlib/authlib/commit/e3bd41cb29dcfee434453b135ffb487884baeedf","tags":["x_refsource_MISC"]},{"url":"https://github.com/authlib/authlib/releases/tag/v1.9.0","name":"https://github.com/authlib/authlib/releases/tag/v1.9.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.4,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-184","lang":"en","description":"CWE-184: Incomplete List of Disallowed Inputs","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-347","lang":"en","description":"CWE-347: Improper Verification of Cryptographic Signature","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-22T21:10:02.023Z"},"source":{"advisory":"GHSA-7vr2-2fgp-9w7p","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/authlib/authlib/security/advisories/GHSA-7vr2-2fgp-9w7p","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-29T02:37:41.689098Z","id":"CVE-2026-114615","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-29T02:38:05.175Z"}}]}}}