{"id":"CVE-2026-75509","aliases":["DEBIAN-CVE-2026-75509","EUVD-2026-65138","GHSA-r74j-q665-7rpj","UBUNTU-CVE-2026-75509"],"status":"published","title":"joserfc claim-validation bypass via array-typed single-string claims (iss/sub/jti)","description":"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.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00124,"percentile":0.02174,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-290","CWE-345"],"published":"2026-08-24T20:08:07Z","modified":"2026-10-28T02:30:45Z","fixes":[{"ecosystem":"Debian:14","package":"joserfc","fixed_in":["1.7.3-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:13","package":"joserfc","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.0-1","1.2.0-1","1.2.2-1","1.3.1-1","1.3.2-1","1.3.4-1","1.4.0-1","1.4.1-1","1.4.3-1","1.5.0-1","1.6.0-1","1.6.1-1","1.6.2-1","1.6.3-1","1.6.4-1","1.6.5-1","1.6.8-1","1.7.0-1","1.7.1-1","1.7.2-1","1.7.3-1","1.7.4-1","1.7.5-1"]},{"source":"osv","ecosystem":"Debian:14","package":"joserfc","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.7.3-1"}]}],"versions":["1.1.0-1","1.2.0-1","1.2.2-1","1.3.1-1","1.3.2-1","1.3.4-1","1.4.0-1","1.4.1-1","1.4.3-1","1.5.0-1","1.6.0-1","1.6.1-1","1.6.2-1","1.6.3-1","1.6.4-1","1.6.5-1","1.6.8-1","1.7.0-1","1.7.1-1","1.7.2-1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"joserfc","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.2-1","1.4.0-1","1.4.1-1","1.4.3-1","1.5.0-1","1.6.2-1"]}],"products":[{"vendor":"authlib","product":"joserfc"}],"references":[{"url":"https://github.com/authlib/joserfc/security/advisories/GHSA-r74j-q665-7rpj","tags":["x_refsource_CONFIRM","exploit","advisory","report"]},{"url":"https://github.com/authlib/joserfc/commit/76ee6a59bf5773c0af00b99076c5e199031f97f1","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/75xxx/CVE-2026-75509.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-75509","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-75509","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-75509","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-75509","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-75509","title":"joserfc claim-validation bypass via array-typed single-string claims (iss/sub/jti)","description":"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.","status":"published","published":"2026-08-24T20:08:07.088Z","modified":"2026-08-25T16:42:19.769Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-290","CWE-345"],"updated_at":"2026-11-02T14:20:07.260654Z"}],"euvd":[{"id":"EUVD-2026-65138","description":"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.","status":"published","published":"2026-08-24T20:08:07Z","modified":"2026-08-25T16:42:19Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T18:01:32.513581Z"}],"nvd":[{"id":"CVE-2026-75509","description":"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.","status":"published","published":"2026-08-24T20:17:19.183Z","modified":"2026-10-12T15:10:00.207Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-290","CWE-345"],"updated_at":"2026-11-02T14:12:41.018848Z"}],"osv":[{"id":"CVE-2026-75509","title":"joserfc claim-validation bypass via array-typed single-string claims (iss/sub/jti)","description":"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.","status":"published","published":"2026-08-24T20:08:07.088Z","modified":"2026-10-28T02:30:45.614825618Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium"}],"cwes":["CWE-290","CWE-345"],"updated_at":"2026-11-02T15:45:17.102988Z"},{"id":"DEBIAN-CVE-2026-75509","description":"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.","status":"published","published":"2026-08-24T20:17:19.183Z","modified":"2026-10-13T10:00:12.206143601Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T15:46:03.004924Z"},{"id":"UBUNTU-CVE-2026-75509","description":"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.","status":"published","published":"2026-08-24T20:17:00Z","modified":"2026-09-02T19:36:33.976629484Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T16:57:13.483205Z"}]}}