{"id":"CVE-2026-102946","state":"PUBLISHED","title":"joserfc: JWS signature verification bypass via empty signatures array in jws.deserialize_json","description":"joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.7.4, joserfc.jws.deserialize_json() accepts a JWS General JSON Serialization with an empty signatures array as authenticated. The verify_general_json() loop performs no iterations for the empty array and returns success because no signature check failed, allowing an attacker without a signing key to supply an arbitrary payload that relying applications may treat as authentic. The issue affects the General JSON Serialization path; compact JWS and JWT decoding, Flattened JSON serialization, and JWE JSON processing do not follow this vulnerable path. This issue is fixed in version 1.7.4.","publishedAt":"2026-10-15T18:28:06.913Z","updatedAt":"2026-10-15T19:53:09.069Z","severity":{"score":9.1,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["authlib joserfc"],"affected":[{"vendor":"authlib","product":"joserfc","versions":[{"version":"< 1.7.4","status":"affected"}]}],"references":["https://github.com/authlib/joserfc/security/advisories/GHSA-4pp3-559j-c5c2","https://github.com/authlib/joserfc/commit/f409f8f058225d7686acab6546c94593e4c1bfbe","https://github.com/authlib/joserfc/releases/tag/1.7.4"],"weaknesses":["CWE-290","CWE-345","CWE-347"],"ingestedAt":"2026-10-29T20:10:13.529Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/102xxx/CVE-2026-102946.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-102946","state":"PUBLISHED","datePublished":"2026-10-15T18:28:06.913Z","dateUpdated":"2026-10-15T19:53:09.069Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-09-29T20:24:43.341Z"},"containers":{"cna":{"title":"joserfc: JWS signature verification bypass via empty signatures array in jws.deserialize_json","descriptions":[{"lang":"en","value":"joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.7.4, joserfc.jws.deserialize_json() accepts a JWS General JSON Serialization with an empty signatures array as authenticated. The verify_general_json() loop performs no iterations for the empty array and returns success because no signature check failed, allowing an attacker without a signing key to supply an arbitrary payload that relying applications may treat as authentic. The issue affects the General JSON Serialization path; compact JWS and JWT decoding, Flattened JSON serialization, and JWE JSON processing do not follow this vulnerable path. This issue is fixed in version 1.7.4."}],"affected":[{"vendor":"authlib","product":"joserfc","versions":[{"version":"< 1.7.4","status":"affected"}]}],"references":[{"url":"https://github.com/authlib/joserfc/security/advisories/GHSA-4pp3-559j-c5c2","name":"https://github.com/authlib/joserfc/security/advisories/GHSA-4pp3-559j-c5c2","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/authlib/joserfc/commit/f409f8f058225d7686acab6546c94593e4c1bfbe","name":"https://github.com/authlib/joserfc/commit/f409f8f058225d7686acab6546c94593e4c1bfbe","tags":["x_refsource_MISC"]},{"url":"https://github.com/authlib/joserfc/releases/tag/1.7.4","name":"https://github.com/authlib/joserfc/releases/tag/1.7.4","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":9.1,"baseSeverity":"CRITICAL","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-290","lang":"en","description":"CWE-290: Authentication Bypass by Spoofing","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-345","lang":"en","description":"CWE-345: Insufficient Verification of Data Authenticity","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":"2026-10-15T18:28:06.913Z"},"source":{"advisory":"GHSA-4pp3-559j-c5c2","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/authlib/joserfc/security/advisories/GHSA-4pp3-559j-c5c2","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-15T19:52:38.661517Z","id":"CVE-2026-102946","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-15T19:53:09.069Z"}}]}}}