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.
Metrics
Affected Vendors & Products
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-x937-hj6v-793p | fast-jwt: Verifier cache accepts expired JWTs without iat. |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 08 Oct 2026 22:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | fast-jwt: Verifier cache accepts expired JWTs without iat. | |
| Weaknesses | CWE-613 | |
| References |
| |
| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-10-08T21:41:55.342Z
Reserved: 2026-10-08T17:21:52.975Z
Link: CVE-2026-107719
No data.
Status : Deferred
Published: 2026-10-08T22:17:27.913
Modified: 2026-10-08T22:17:28.053
Link: CVE-2026-107719
No data.
OpenCVE Enrichment
No data.
Weaknesses
Github GHSA