CVE-2026-35042
fast-jwt accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)
Summary
fast-jwt accepts unknown crit header extensions (RFC 7515 §4.1.11 MUST violation)
Original description
The description as published by the source.
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.
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- web rfc-editor.org