Vulnerability Description
fast-jwt provides fast JSON Web Token (JWT) implementation. From 0.0.1 to before 6.2.0, setting up a custom cacheKeyBuilder method which does not properly create unique keys for different tokens can lead to cache collisions. This could cause tokens to be mis-identified during the verification process leading to valid tokens returning claims from different valid tokens and users being mis-identified as other users based on the wrong token. Version 6.2.0 contains a patch.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nearform | Fast-Jwt | >= 0.1.0, < 6.1.0 |
Related Weaknesses (CWE)
References
- https://github.com/nearform/fast-jwt/commit/de121056c6415b58770c60640881eaec67acPatch
- https://github.com/nearform/fast-jwt/security/advisories/GHSA-rp9m-7r4c-75qgMitigationVendor Advisory
FAQ
What is CVE-2026-35039?
CVE-2026-35039 is a vulnerability with a CVSS score of 9.1 (CRITICAL). fast-jwt provides fast JSON Web Token (JWT) implementation. From 0.0.1 to before 6.2.0, setting up a custom cacheKeyBuilder method which does not properly create unique keys for different tokens can l...
How severe is CVE-2026-35039?
CVE-2026-35039 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-35039?
Check the references section above for vendor advisories and patch information. Affected products include: Nearform Fast-Jwt.