{"id":"UBUNTU-CVE-2026-25537","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.","modified":"2026-05-20T16:24:46.698724088Z","published":"2026-02-04T22:15:00Z","upstream":["CVE-2026-25537"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-25537"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-25537"},{"type":"REPORT","url":"https://github.com/Keats/jsonwebtoken/commit/abbc3076742c4161347bc6b8bf4aa5eb86e1dc01"},{"type":"REPORT","url":"https://github.com/Keats/jsonwebtoken/security/advisories/GHSA-h395-gr6q-cpjc"}],"affected":[{"package":{"name":"rust-jsonwebtoken","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/rust-jsonwebtoken?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["8.3.0-1","8.3.0-3"],"ecosystem_specific":{"binaries":[{"binary_version":"8.3.0-3","binary_name":"librust-jsonwebtoken-dev"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-25537.json"}},{"package":{"name":"rust-jsonwebtoken","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/rust-jsonwebtoken?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["8.3.0-5"],"ecosystem_specific":{"binaries":[{"binary_name":"librust-jsonwebtoken-dev","binary_version":"8.3.0-5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-25537.json"}},{"package":{"name":"rust-jsonwebtoken","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/rust-jsonwebtoken?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["8.3.0-5","9.3.1-1"],"ecosystem_specific":{"binaries":[{"binary_version":"9.3.1-1","binary_name":"librust-jsonwebtoken-dev"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-25537.json"}}],"schema_version":"1.7.5","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"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}