nearform fast-jwt up to 6.2.x Key Detection src/crypto.js performDetectPublicKeyAlgorithms authorization

Summaryinfo

A vulnerability marked as critical has been reported in nearform fast-jwt up to 6.2.x. Impacted is the function performDetectPublicKeyAlgorithms of the file src/crypto.js of the component Key Detection. Performing a manipulation results in authorization. This vulnerability is cataloged as CVE-2026-107722. It is possible to initiate the attack remotely. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in nearform fast-jwt up to 6.2.x. This affects the function performDetectPublicKeyAlgorithms of the file src/crypto.js of the component Key Detection. The manipulation with an unknown input leads to a authorization vulnerability. CWE is classifying the issue as CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-107722 since 10/08/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available.

Upgrading to version 6.3.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-95347). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• nearform

Name

• fast-jwt

Version

• 6.0
• 6.1
• 6.2

Website

• Product: https://github.com/nearform/fast-jwt/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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