CVE-2026-44351-poc

CVE-2026-44351 — JWT Forgery via Empty Secret in fast-jwt PoC of the authentication bypass auth bypass in fast-jwt versions prior to 6.2.4 that allows any unauthenticated attacker to forge arbitrary JWTs and have them accepted as authentic by the target application. | ---|--- CVE| CVE-2026-44351...

CVE-2023-48223

CVE-2023-48223 PoC fast-jwt Algorithm Confusion This repository demonstrates JWT algorithm confusion in fast-jwt when token verification does not lock allowed algorithms. Environment Setup Requirements Node.js 18 or newer npm OpenSSL must be available in your terminal PATH 1 Install dependencies...

CVE-2025-30144

Summary The fast-jwt library does not properly validate the iss claim based on the RFC https://datatracker.ietf.org/doc/html/rfc7519page-9. Details The iss issuer claim validation within the fast-jwt library permits an array of strings as a valid iss value. This design flaw enables a potential...

CVE-2026-107722

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 publicKeyPemMatch...

CVE-2026-107720

fast-jwt provides fast JSON Web Token JWT implementation. Prior to 6.3.1, fast-jwt createVerifier accepts an unsigned JWT when key is an empty string or null and algorithms is a non-empty allowlist. Falsy synchronous keys bypass prepareKeyOrSecret, allowedAlgorithms remains active, hasKey is fals...

CVE-2026-107721

fast-jwt provides fast JSON Web Token JWT implementation. Prior to 6.3.0, fast-jwt createVerifier accepts Infinity for clockTolerance because its option validation checks type and negativity but not finiteness. In validateClaimDateValue, infinite positive and negative modifiers make exp and nbf...

CVE-2026-107724

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, a...

CVE-2026-107723

fast-jwt provides fast JSON Web Token JWT implementation. Prior to 6.3.0, fast-jwt createVerifier accepts a validly signed JWT whose payload is a JSON array because src/decoder.js checks that the payload is an object but does not reject arrays. The claim validator loop then finds no named exp, nb...

CVE-2026-107719

fast-jwt provides fast JSON Web Token JWT implementation. Prior to 6.3.4, the fast-jwt createVerifier cache can continue accepting a previously valid, signed JWT after its exp time when caching is enabled and the token has exp but no iat. In src/verifier.js, cacheSet derives the exp cache deadlin...

GHSA-X937-HJ6V-793P fast-jwt: Verifier cache accepts expired JWTs without iat.

Summary cacheSet only derives its exp cache deadline inside hasIat src/verifier.js:127-140. JWT iat is optional. For a valid token with exp but no iat, cacheSet substitutes clockTimestamp + clockTolerance + cacheTTL src/verifier.js:142-146. Later, the cache path returns the saved payload before...

NPM: fast-jwt: Verifier cache accepts expired JWTs without iat.

NPM: fast-jwt: Verifier cache accepts expired JWTs without iat. vulnerability discovered by ? in WordPress Npm fast-jwt versions = 6.3.3...

fast-jwt: Verifier cache accepts expired JWTs without iat.

Summary cacheSet only derives its exp cache deadline inside hasIat src/verifier.js:127-140. JWT iat is optional. For a valid token with exp but no iat, cacheSet substitutes clockTimestamp + clockTolerance + cacheTTL src/verifier.js:142-146. Later, the cache path returns the saved payload before...

@jsprismarine/client (>=0.1.0-rc.50, <=0.14.2), @jsprismarine/prismarine (>=0.12.2-unstable-20250320195345, <=0.14.2) +2 more potentially affected by CVE-2026-107719 via fast-jwt (>=6.0.0, <=6.3.3)

fast-jwt NPM version =6.0.0, =0.1.0-rc.50, =0.12.2-unstable-20250320195345, =0.1.0-rc.50, =0.1.0-rc.50, =0.1.0-rc.52 Source cves: CVE-2026-107719 Source advisory: OSV:GHSA-X937-HJ6V-793P...

@jsprismarine/client (>=0.1.0-rc.50, <=0.14.2), @jsprismarine/prismarine (>=0.12.2-unstable-20250320195345, <=0.14.2) +2 more potentially affected by CVE-2026-107719 via fast-jwt (>=6.0.0, <=6.3.3)

fast-jwt NPM version =6.0.0, =0.1.0-rc.50, =0.12.2-unstable-20250320195345, =0.1.0-rc.50, =0.1.0-rc.50, =0.1.0-rc.52 Source cves: CVE-2026-107719 Source advisory: SNYK:JS-FASTJWT-20825051...

@jsprismarine/client (>=0.1.0-rc.50, <=0.14.2), @jsprismarine/prismarine (>=0.12.2-unstable-20250320195345, <=0.14.2) +2 more potentially affected by CVE-2026-107719 via fast-jwt (>=6.0.0, <=6.3.3)

fast-jwt NPM version =6.0.0, =0.1.0-rc.50, =0.12.2-unstable-20250320195345, =0.1.0-rc.50, =0.1.0-rc.50, =0.1.0-rc.52 Source cves: CVE-2026-107719 Source advisory: GHSA-X937-HJ6V-793P...

Insufficient Session Expiration

Overview fast-jwt is a Fast JSON Web Token implementation Affected versions of this package are vulnerable to Insufficient Session Expiration via the verifier cache in src/verifier.js, where the cacheSet function only derived exp and nbf bounds from a token's payload when the iat claim was also...

@jsprismarine/client (>=0.12.2-unstable-20250320195345, <=0.14.1), @jsprismarine/prismarine (>=0.12.2-unstable-20250320195345, <=0.14.1) +1 more potentially affected by CVE-2026-107720 via fast-jwt (>=6.0.0, <=6.2.4)

fast-jwt NPM version =6.0.0, =0.12.2-unstable-20250320195345, =0.12.2-unstable-20250320195345, =0.12.2-unstable-20250320195345, =0.14.1 Source cves: CVE-2026-107720 Source advisory: SNYK:JS-FASTJWT-20825050...

@jsprismarine/client (>=0.12.2-unstable-20250320195345, <=0.14.1), @jsprismarine/prismarine (>=0.12.2-unstable-20250320195345, <=0.14.1) +1 more potentially affected by CVE-2026-107720 via fast-jwt (>=6.0.0, <=6.2.4)

fast-jwt NPM version =6.0.0, =0.12.2-unstable-20250320195345, =0.12.2-unstable-20250320195345, =0.12.2-unstable-20250320195345, =0.14.1 Source cves: CVE-2026-107720 Source advisory: OSV:GHSA-8WPC-H4Q6-8FXV...

@jsprismarine/client (>=0.12.2-unstable-20250320195345, <=0.14.1), @jsprismarine/prismarine (>=0.12.2-unstable-20250320195345, <=0.14.1) +1 more potentially affected by CVE-2026-107720 via fast-jwt (>=6.0.0, <=6.2.4)

fast-jwt NPM version =6.0.0, =0.12.2-unstable-20250320195345, =0.12.2-unstable-20250320195345, =0.12.2-unstable-20250320195345, =0.14.1 Source cves: CVE-2026-107720 Source advisory: GHSA-8WPC-H4Q6-8FXV...

NPM: fast-jwt: createVerifier accepts unsigned JWTs when key is '' or null and algorithms is explicitly set

NPM: fast-jwt: createVerifier accepts unsigned JWTs when key is '' or null and algorithms is explicitly set vulnerability discovered by ? in WordPress Npm fast-jwt versions = 6.3.0...