CVE-2026-107719fast-jwt: Verifier cache accepts expired JWTs without iat.
Updated under an hour ago ()
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It affects nearform fast-jwt. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 4.2 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
- Weakness (CWE)
- CWE-613
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Oct 9, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
nearform fast-jwt nearform:fast_jwt (from the name) | before 6.3.4 | CNA record |
References
- https://github.com/nearform/fast-jwt/security/advisories/GHSA-x937-hj6v-793px-refsource-confirm
- https://github.com/nearform/fast-jwt/commit/fc1ddbbe5ce38066ba2cea0b0ce0233932757167x-refsource-misc
- https://github.com/nearform/fast-jwt/releases/tag/v6.3.4x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.