Vulnerability in Nearform Fast-Jwt
CVE-2026-107719
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.2 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Nearform Fast-Jwt — versions < 6.3.4
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-107719?
- CVE-2026-107719 is a medium-severity vulnerability in Nearform Fast-Jwt, classified under Insufficient Session Expiration. CVSS score: 4.2/10. Published 2026-10-08.
- How severe is CVE-2026-107719?
- Medium severity. CVSS v3 base score is 4.2 out of 10.