CVE-2026-107722
fast-jwt: Incomplete patch of CVE-2026-34950: Non-whitespace key-prefix re-enables RSA→HS256 algorithm confusion
The fix for CVE-2026-34950 (CVSS 9.1, released in v6.2.0) is incomplete. It adds key.trim() to the PEM-detection path in src/crypto.js, but String.prototype.trim() only strips characters classified as whitespace by the ECMAScript specification. The subsequent ^-anchored regex (/^-----BEGIN(?: (RSA))?
- No known exploitation
- Severity
- Critical, CVSS 9.8 (v3.1)
- EPSS
- 0.27% chance of exploitation in 30 days (EPSS, as of Oct 23, 2026)
- Affected packages
- fast-jwt (npm) >= 6.2.0, <= 6.2.4, fixed in 6.3.0 · GHSA-ww5h-9m49-7xx4