ruby-jwt: Empty-key HMAC bypass; cross-language sibling of CVE-2026-44351

JWT.decodetoken, '', true, algorithm: 'HS256' accepts an attacker-forged token. OpenSSL::HMAC.digest'SHA256', '', payload returns a valid digest under an empty key, and no raise InvalidKeyError if key.empty? precondition exists in the HMAC algorithm. JWT.decodetoken, "", true, algorithm: 'HS256' ...

CVE-2026-44351

fast-jwt provides fast JSON Web Token JWT implementation. Prior to 6.2.4, a critical authentication-bypass vulnerability in fast-jwt's async key-resolver flow allows any unauthenticated attacker to forge arbitrary JWTs that are accepted as authentic. When the application's key resolver returns an...

CVE-2026-44351

fast-jwt provides fast JSON Web Token JWT implementation. Prior to 6.2.4, a critical authentication-bypass vulnerability in fast-jwt's async key-resolver flow allows any unauthenticated attacker to forge arbitrary JWTs that are accepted as authentic. When the application's key resolver returns an...

@jsprismarine/client (>=0.12.2-unstable-20250320195345 <=0.13.1-unstable-20250503082416), @jsprismarine/prismarine (>=0.12.2-unstable-20250320195345 <=0.13.1-unstable-20250503082416) +1 more potentially affected by CVE-2026-44351 via fast-jwt (>=6.0.0 <=6.0.1)

fast-jwt NPM version =6.0.0, =0.12.2-unstable-20250320195345, =0.12.2-unstable-20250320195345, =0.12.2-unstable-20250320195345, =0.13.1-unstable-20250503082416 Source cves: CVE-2026-44351 Source advisory: SNYK:JS-FASTJWT-16439016...

CVE-2026-44351

creationtimestamp| type| source ---|---|--- 2026-04-29 11:07:21+00:00| published-proof-of-concept| https://github.com/nearform/fast-jwt/security/advisories/GHSA-gmvf-9v4p-v8jc...