CVE-2026-35042
Last modified
CVE-2026-35042 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, fast-jwt does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. EPSS estimates a 0.15% chance of exploitation in the next 30 days.
Description
fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, fast-jwt does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. When a JWS token contains a crit array listing extensions that fast-jwt does not understand, the library accepts the token instead of rejecting it. This violates the MUST requirement in the RFC.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Nearform | Fast-Jwt | < 6.2.0 |
References
- https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6Exploit, Mitigation, Vendor Advisory
- https://www.rfc-editor.org/rfc/rfc7515.html#section-4.1.11Technical Description
- https://github.com/nearform/fast-jwt/security/advisories/GHSA-hm7r-c7qw-ghp6Exploit, Mitigation, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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How Strix Helps
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