{"id":"CVE-2026-107721","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-107721","generatedAt":"2026-10-28T02:12:49.959Z","title":"In validateClaimDateValue, infinite positive and negative modifiers make exp and nbf comparisons always pass, allowing expired or not-yet-active tokens to be accepted.","description":"fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.0, fast-jwt createVerifier accepts Infinity for clockTolerance because its option validation checks type and negativity but not finiteness. In validateClaimDateValue, infinite positive and negative modifiers make exp and nbf comparisons always pass, allowing expired or not-yet-active tokens to be accepted. The verifier cache also derives infinite bounds, so entries created under this configuration can remain valid until eviction. Exploitation requires an application administrator or equivalent configuration path to set clockTolerance to Infinity. This issue is fixed in version 6.3.0.","published":"2026-10-08T22:17:28.000Z","lastModified":"2026-10-09T16:17:24.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N"},"cwe":["CWE-613","CWE-682"],"affected":[],"epss":{"score":0.00341,"percentile":0.27419,"date":"2026-10-26","history":[{"date":"2026-10-09","score":0.00334,"percentile":0.24811}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.34%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-08T22:17:28.000Z","detail":{"score":"5.9","severity":"MEDIUM","publishedAt":"2026-10-08T22:17:28.263Z"},"summary":"New CVE, medium severity (CVSS 5.9)."}],"references":[{"url":"https://github.com/nearform/fast-jwt/commit/c0fb5b88b4c88ff2bdd194ca2c713599ad9e38b6","source":"security-advisories@github.com"},{"url":"https://github.com/nearform/fast-jwt/releases/tag/v6.3.0","source":"security-advisories@github.com"},{"url":"https://github.com/nearform/fast-jwt/security/advisories/GHSA-687g-22h4-j4w4","source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-107721","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}