{"id":"CVE-2026-114616","state":"PUBLISHED","title":"Authlib accepts an empty HMAC key, allowing JWS/JWT signature forgery (HS256/HS384/HS512)","description":"Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.1, Authlib's OctKey.import_key() and HMAC signing and verification path accept zero-length key material. If an application's secret lookup can return an empty string or empty bytes, a remote attacker can compute the deterministic HS256, HS384, or HS512 signature for arbitrary token claims and have Authlib treat the token as authentic. This issue is fixed in version 1.9.1.","publishedAt":"2026-10-22T21:14:03.060Z","updatedAt":"2026-10-30T20:07:37.170Z","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":"< 1.9.1","status":"affected"}]}],"references":["https://github.com/authlib/authlib/security/advisories/GHSA-8m4g-j4wp-wgcg","https://github.com/authlib/authlib/commit/4ff30db442c70e29486e1982cb0ad37c037f5f4b","https://github.com/authlib/authlib/releases/tag/v1.9.1"],"weaknesses":["CWE-287","CWE-326","CWE-1391"],"ingestedAt":"2026-10-30T20:14:06.645Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/114xxx/CVE-2026-114616.json","commit":"d7f5c3fe206091a44e450f13bfe51dc81b8a7843","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-114616","state":"PUBLISHED","datePublished":"2026-10-22T21:14:03.060Z","dateUpdated":"2026-10-30T20:07:37.170Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-10-21T20:34:25.600Z"},"containers":{"cna":{"title":"Authlib accepts an empty HMAC key, allowing JWS/JWT signature forgery (HS256/HS384/HS512)","descriptions":[{"lang":"en","value":"Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.1, Authlib's OctKey.import_key() and HMAC signing and verification path accept zero-length key material. If an application's secret lookup can return an empty string or empty bytes, a remote attacker can compute the deterministic HS256, HS384, or HS512 signature for arbitrary token claims and have Authlib treat the token as authentic. This issue is fixed in version 1.9.1."}],"affected":[{"vendor":"authlib","product":"authlib","versions":[{"version":"< 1.9.1","status":"affected"}]}],"references":[{"url":"https://github.com/authlib/authlib/security/advisories/GHSA-8m4g-j4wp-wgcg","name":"https://github.com/authlib/authlib/security/advisories/GHSA-8m4g-j4wp-wgcg","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/authlib/authlib/commit/4ff30db442c70e29486e1982cb0ad37c037f5f4b","name":"https://github.com/authlib/authlib/commit/4ff30db442c70e29486e1982cb0ad37c037f5f4b","tags":["x_refsource_MISC"]},{"url":"https://github.com/authlib/authlib/releases/tag/v1.9.1","name":"https://github.com/authlib/authlib/releases/tag/v1.9.1","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-287","lang":"en","description":"CWE-287: Improper Authentication","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-326","lang":"en","description":"CWE-326: Inadequate Encryption Strength","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-1391","lang":"en","description":"CWE-1391: Use of Weak Credentials","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-22T21:14:03.060Z"},"source":{"advisory":"GHSA-8m4g-j4wp-wgcg","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-30T20:07:25.381279Z","id":"CVE-2026-114616","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-30T20:07:37.170Z"}}]}}}