7.4

CVE-2026-107724

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

fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.2.4, fast-jwt can classify raw serialized public JWK or JWKS JSON as an HMAC secret because src/crypto.js performDetectPublicKeyAlgorithms treats non-PEM strings as symmetric key material. If HS256 is explicitly allowed or inferred, an attacker who knows the exact serialized public-key bytes can use those bytes as an HMAC key and create a token containing arbitrary claims that createVerifier accepts. Serialization ordering or whitespace differences can prevent exploitation, and applications using supported PEM keys with an asymmetric-only algorithm allowlist are not affected. This issue is fixed in version 6.3.0.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
Herstellernearform
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Produkt fast-jwt
Version >= 6.2.4, < 6.3.0
Status affected
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.22% 0.117
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 7.4 2.2 5.2
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE-347 Improper Verification of Cryptographic Signature

The product does not verify, or incorrectly verifies, the cryptographic signature for data.

https://github.com/nearform/fast-jwt/releases/tag/v6.3.0
https://github.com/nearform/fast-jwt/security/advisories/GHSA-g3jj-5cmm-3hxx
https://github.com/nearform/fast-jwt/pull/636
https://github.com/nearform/fast-jwt/commit/10f9591349199ed2ab9fa1748ce92cdca697f6cf