{"id":"CVE-2021-46743","details":"In Firebase PHP-JWT before 6.0.0, an algorithm-confusion issue (e.g., RS256 / HS256) exists via the kid (aka Key ID) header, when multiple types of keys are loaded in a key ring. This allows an attacker to forge tokens that validate under the incorrect key. NOTE: this provides a straightforward way to use the PHP-JWT library unsafely, but might not be considered a vulnerability in the library itself.","aliases":["GHSA-8xf4-w7qw-pjjw"],"modified":"2026-08-27T08:15:13.921421Z","published":"2022-03-29T07:15:07.017Z","references":[{"type":"EVIDENCE","url":"https://github.com/firebase/php-jwt/issues/351"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/googleapis/php-jwt","events":[{"introduced":"0"},{"fixed":"0541cba75ab108ef901985e68055a92646c73534"}],"database_specific":{"cpe":"cpe:2.3:a:google:firebase_php-jwt:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"6.0.0"}],"source":"CPE_RANGE"}}],"versions":["v5.5.1","v5.5.0","v5.4.0","v5.3.0","v5.2.1","v5.2.0","v5.1.0","v5.0.0","v4.0.0","v3.0.0","v2.2.0","v2.1.0","v2.0.0","v1.0.0","v0.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-46743.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}