{"id":"DEBIAN-CVE-2026-102266","details":"PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently, forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0.","modified":"2026-09-30T09:00:10.372425180Z","published":"2026-09-28T21:17:14.257Z","upstream":["CVE-2026-102266"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-102266"}],"affected":[{"package":{"name":"pyjwt","ecosystem":"Debian:12","purl":"pkg:deb/debian/pyjwt?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.1-1","2.10.1-2","2.10.1-3","2.10.1-4","2.11.0-2","2.12.1-1","2.13.0-1","2.14.0-1","2.15.0-1","2.15.1-1","2.6.0-1","2.6.0-1+deb12u1","2.7.0-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-102266.json"}},{"package":{"name":"pyjwt","ecosystem":"Debian:13","purl":"pkg:deb/debian/pyjwt?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.1-2","2.10.1-2+deb13u1","2.10.1-3","2.10.1-4","2.11.0-2","2.12.1-1","2.13.0-1","2.14.0-1","2.15.0-1","2.15.1-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-102266.json"}},{"package":{"name":"pyjwt","ecosystem":"Debian:14","purl":"pkg:deb/debian/pyjwt?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.1-2","2.10.1-3","2.10.1-4","2.11.0-2","2.12.1-1","2.13.0-1","2.14.0-1","2.15.0-1","2.15.1-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-102266.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}