fast-jwt treats raw public JWK JSON as an HMAC secret, enabling HS256 token forgery

Date Oct 8, 2026
Type Vendor advisory
Signal High-risk advisory
Vendor / Product npm ยท fast-jwt
CVE CVE-2026-107724
High-risk advisory CVE-2026-107724

Summary

fast-jwt treats raw public JWK JSON as an HMAC secret, enabling HS256 token forgery

Why it matters

GitHub has published a reviewed security advisory for fast-jwt. Prioritize it with other application dependency updates, especially because EPSS places it in the 12% percentile.

Operator check

Check whether fast-jwt is present in application dependency manifests, lockfiles, or build images. Review the GitHub advisory and upgrade to a patched version where available. EPSS probability: 0.2%; percentile: 12%.

Sources

PatchBrief uses public sources. It does not scan environments, verify exposure, or replace vendor guidance.