CVE-2026-107719: medium-severity vulnerability in nearform fast-jwt
fast-jwt: Verifier cache accepts expired JWTs without iat.
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 4.2epss 0.3%
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:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
Affected products
nearform · fast-jwtRelated CVEs — nearform fast-jwt
In the same product, most dangerous first.
CVE-2023-48223MEDIUMfast-jwt JWT Algorithm ConfusionEPSS 0.7%CVE-2025-30144MEDIUMFast-JWT Improperly Validates iss ClaimsEPSS 0.6%CVE-2026-107723HIGHfast-jwt : Silent claim-validator bypass when JWT payload is a JSON arrayEPSS 0.5%CVE-2026-35040MEDIUMfast-jwt: Stateful RegExp (/g or /y) causes non-deterministic allowed-claim validation (logical DoS)EPSS 0.4%CVE-2026-107722CRITICALfast-jwt: Incomplete patch of CVE-2026-34950: Non-whitespace key-prefix re-enables RSA→HS256 algorithm confusionEPSS 0.4%CVE-2026-107721MEDIUMfast-jwt clockTolerance: Infinity silently bypasses both exp and nbf validation (and persists in the verifier cache)EPSS 0.3%