{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-75509", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-08-17T20:49:21.598Z", "datePublished": "2026-08-24T20:08:07.088Z", "dateUpdated": "2026-08-24T20:08:07.088Z"}, "containers": {"cna": {"title": "joserfc claim-validation bypass via array-typed single-string claims (iss/sub/jti)", "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"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N", "version": "3.1"}}], "references": [{"name": "https://github.com/authlib/joserfc/security/advisories/GHSA-r74j-q665-7rpj", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/authlib/joserfc/security/advisories/GHSA-r74j-q665-7rpj"}, {"name": "https://github.com/authlib/joserfc/commit/76ee6a59bf5773c0af00b99076c5e199031f97f1", "tags": ["x_refsource_MISC"], "url": "https://github.com/authlib/joserfc/commit/76ee6a59bf5773c0af00b99076c5e199031f97f1"}], "affected": [{"vendor": "authlib", "product": "joserfc", "versions": [{"version": "< 1.7.3", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-08-24T20:08:07.088Z"}, "descriptions": [{"lang": "en", "value": "joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version 1.7.3, JWTClaimsRegistry applies membership matching to list-valued iss and sub claims, allowing an array-valued iss that contains the expected issuer to pass an intended equality check and enabling issuer-validation bypass. This issue is fixed in version 1.7.3."}], "source": {"advisory": "GHSA-r74j-q665-7rpj", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "joserfc", "vendor": "authlib", "versions": [{"status": "affected", "version": "< 1.7.3"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version 1.7.3, JWTClaimsRegistry applies membership matching to list-valued iss and sub claims, allowing an array-valued iss that contains the expected issuer to pass an intended equality check and enabling issuer-validation bypass. This issue is fixed in version 1.7.3."}], "id": "CVE-2026-75509", "lastModified": "2026-08-24T20:17:19.183", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 4.2, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-08-24T20:17:19.183", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/authlib/joserfc/commit/76ee6a59bf5773c0af00b99076c5e199031f97f1"}, {"source": "security-advisories@github.com", "url": "https://github.com/authlib/joserfc/security/advisories/GHSA-r74j-q665-7rpj"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-290"}, {"lang": "en", "value": "CWE-345"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{}