{"id":"CVE-2026-25537","summary":"jsonwebtoken has Type Confusion that leads to potential authorization bypass","details":"jsonwebtoken is a JWT lib in rust. Prior to version 10.3.0, there is a Type Confusion vulnerability in jsonwebtoken, specifically, in its claim validation logic. When a standard claim (such as nbf or exp) is provided with an incorrect JSON type (Like a String instead of a Number), the library’s internal parsing mechanism marks the claim as “FailedToParse”. Crucially, the validation logic treats this “FailedToParse” state identically to “NotPresent”. This means that if a check is enabled (like: validate_nbf = true), but the claim is not explicitly marked as required in required_spec_claims, the library will skip the validation check entirely for the malformed claim, treating it as if it were not there. This allows attackers to bypass critical time-based security restrictions (like “Not Before” checks) and commit potential authentication and authorization bypasses. This issue has been patched in version 10.3.0.","aliases":["GHSA-h395-gr6q-cpjc"],"modified":"2026-08-12T03:51:08.648487541Z","published":"2026-02-04T21:31:53.511Z","related":["CGA-gpjx-p7hc-6rc6"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25537.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-843"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25537.json"},{"type":"ADVISORY","url":"https://github.com/Keats/jsonwebtoken/security/advisories/GHSA-h395-gr6q-cpjc"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-25537"},{"type":"FIX","url":"https://github.com/Keats/jsonwebtoken/commit/abbc3076742c4161347bc6b8bf4aa5eb86e1dc01"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/keats/jsonwebtoken","events":[{"introduced":"0"},{"fixed":"abbc3076742c4161347bc6b8bf4aa5eb86e1dc01"}],"database_specific":{"cpe":"cpe:2.3:a:keats:jsonwebtoken:*:*:*:*:*:rust:*:*","extracted_events":[{"introduced":"0"},{"fixed":"10.3.0"}],"source":["AFFECTED_FIELD","CPE_RANGE","REFERENCES"]}}],"versions":["v10.2.0","v10.1.0","v10.0.0","v9.3.1","v9.3.0","v9.2.0","v9.1.0","v9.0.0","v8.3.0","v8.2.0","v8.1.1","v8.1.0","v8.0.1","v8.0.0","v7.2.0","v7.1.2","v7.1.1","v7.0.1","v2.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-25537.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P"}]}