CVE-2026-107721Medium· 5.9▾ Sunlitfast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.0, fast-jwt createVerifier accepts Infinity for clockTolerance because its option validation checks type and negativity but not finiteness. In validateClaimDateValu…
▾ Sunlit zone — Low / medium · no exploitation signal
impact 32.5 · likelihood 0 · exploitation 0
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fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.0, fast-jwt createVerifier accepts Infinity for clockTolerance because its option validation checks type and negativity but not finiteness. In validateClaimDateValue, infinite positive and negative modifiers make exp and nbf comparisons always pass, allowing expired or not-yet-active tokens to be accepted. The verifier cache also derives infinite bounds, so entries created under this configuration can remain valid until eviction. Exploitation requires an application administrator or equivalent configuration path to set clockTolerance to Infinity. This issue is fixed in version 6.3.0.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
fast-jwt <= 6.2.4Patched in:
fast-jwt 6.3.0Connected by shared product, vendor, weakness, or advisory.
CVE-2026-107724High· 7.4fast-jwt provides fast JSON Web Token (JWT) implementation
CVE-2026-107723High· 8.1fast-jwt provides fast JSON Web Token (JWT) implementation
CVE-2026-107722Critical· 9.8fast-jwt provides fast JSON Web Token (JWT) implementation
CVE-2026-107719Medium· 4.2fast-jwt provides fast JSON Web Token (JWT) implementation
CVE-2026-107720High· 7.4fast-jwt provides fast JSON Web Token (JWT) implementation
CVE-2025-54547Medium· 5.3On affected platforms, if SSH session multiplexing was configured on the client side, SSH sessions (e.g, scp, sftp) multiplexed onto the same channel could perform file-system operations after a configured session timeout expired