{"cve":"CVE-2026-107721","nvd":{"published":"2026-10-08T22:17:28.263","modified":"2026-10-09T16:17:23.590","status":"Deferred","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N","score":5.9},"cwes":["CWE-613","CWE-682"],"references":["https://github.com/nearform/fast-jwt/commit/c0fb5b88b4c88ff2bdd194ca2c713599ad9e38b6","https://github.com/nearform/fast-jwt/releases/tag/v6.3.0","https://github.com/nearform/fast-jwt/security/advisories/GHSA-687g-22h4-j4w4"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:58:01.639778232+00:00"},"epss":{"cve":"CVE-2026-107721","score":0.00341,"percentile":0.27386,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-687g-22h4-j4w4","url":"https://osv.dev/vulnerability/GHSA-687g-22h4-j4w4","summary":"fast-jwt clockTolerance: Infinity silently bypasses both exp and nbf validation (and persists in the verifier cache)","modified":"2026-10-08T22:15:05.893519907Z","packages":[{"ecosystem":"npm","name":"fast-jwt","purl":"pkg:npm/fast-jwt","ranges":["<6.3.0"],"fixed":["6.3.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}