CVE-2026-107721

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.

CVSS v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 0.7 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required HIGH

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/nearform/fast-jwt/commit/c0fb5b88b4c88ff2bdd194ca2c713599ad9e38b6
https://github.com/nearform/fast-jwt/releases/tag/v6.3.0
https://github.com/nearform/fast-jwt/security/advisories/GHSA-687g-22h4-j4w4

Configurations

No configuration.

History

08 Oct 2026, 22:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-08 22:17

Updated : 2026-10-09 16:17

NVD link : CVE-2026-107721

Mitre link : CVE-2026-107721

CVE.ORG link : CVE-2026-107721

JSON object : View

Products Affected

No product.

CWE

CWE-613

Insufficient Session Expiration

CWE-682

Incorrect Calculation

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