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CVE-2026-35042

CVE-2026-35042 · fast-jwt accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 7.5 · High · EPSS 0.2%

Published
Updated

Stack: node

Affected products and versions

  • fast-jwt

    Versions
    • <= 6.1.0: Affected

    No fix published

  • fast-jwt npm

    Affected ranges
    • SEMVER: ≤ 6.1.0

    No fix published

Original sources

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