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CVE-2026-34950

CVE-2026-34950 · fast-jwt has an incomplete fix for CVE-2023-48223: JWT Algorithm Confusion via Whitespace-Prefixed RSA Public Key

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, the publicKeyPemMatcher regex in fast-jwt/src/crypto.js uses a ^ anchor that is defeated by any leading whitespace in the key string, re-enabling the exact same JWT algorithm confusion attack that CVE-2023-48223 patched.

CVSS 9.1 · Critical · EPSS 0.2% · Fix available

Published
Updated

Stack: node

Affected products and versions

  • fast-jwt

    Versions
    • <= 6.1.0: Affected

    No fix published

  • fast-jwt npm

    Affected ranges
    • SEMVER: < 6.2.0

    Update to 6.2.0

Original sources

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