fast-jwt provides fast JSON Web Token (JWT) implementation. From 6.2.0 until 6.3.0, fast-jwt can misclassify RSA public-key text as an HMAC secret when the key has non-whitespace content before its PEM header. In src/crypto.js, performDetectPublicKeyAlgorithms trims whitespace but publicKeyPemMatcher remains start-anchored, so comments, control characters, zero-width characters, or wrapper text can prevent PEM detection and reach the HMAC fallback. An attacker who knows the public key bytes can sign arbitrary HS256 claims with that public material when HS256 is inferred or allowed, resulting in authentication or authorization bypass. An asymmetric-only algorithm allowlist prevents the attack. This issue is fixed in version 6.3.0.
References
Configurations
No configuration.
History
13 Oct 2026, 17:17
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://github.com/nearform/fast-jwt/security/advisories/GHSA-ww5h-9m49-7xx4 - |
08 Oct 2026, 22:17
| Type | Values Removed | Values Added |
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| New CVE |
Information
Published : 2026-10-08 22:17
Updated : 2026-10-13 17:17
NVD link : CVE-2026-107722
Mitre link : CVE-2026-107722
CVE.ORG link : CVE-2026-107722
JSON object : View
Products Affected
No product.
CWE
CWE-347
Improper Verification of Cryptographic Signature
