fast-jwt: Verifier cache accepts expired JWTs without iat. (nearform fast-jwt)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.27 % · percentile 20 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Deferred
Description
fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.4, the fast-jwt createVerifier cache can continue accepting a previously valid, signed JWT after its exp time when caching is enabled and the token has exp but no iat. In src/verifier.js, cacheSet derives the exp cache deadline only when iat is present, so the cache falls back to cacheTTL, and a later cache hit returns the saved payload before verifyToken rechecks expiration. An attacker who can replay the same cached bearer token can extend access until the cache entry expires, but cannot forge a token through this issue. This issue is fixed in version 6.3.4.
Weaknesses (CWE)
- CWE-613 — DEPRECATED: Insufficient Session Expiration
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 4.2 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N | GitHub_M |
| CVSS 3.1 | MEDIUM 4.2 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-x937-hj6v-793p — fast-jwt: Verifier cache accepts expired JWTs without iat.
European references
- ENISA EUVD · EUVD-2026-95343
- GCVE · GCVE-0-2026-107719
Affected products
| Product | Versions |
|---|---|
| nearform · fast-jwt | affected < 6.3.4 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |