Summaryinfo

A vulnerability has been found in benmcollins libjwt up to 3.2.x and classified as problematic. The affected element is an unknown function of the component JWK Parser. Performing a manipulation results in null pointer dereference. This vulnerability was named CVE-2026-33996. The attack needs to be approached within the local network. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, was found in benmcollins libjwt up to 3.2.x. This affects an unknown part of the component JWK Parser. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

LibJWT is a C JSON Web Token Library. Starting in version 3.0.0 and prior to version 3.3.0, the JWK parsing for RSA-PSS did not protect against a NULL value when expecting to parse JSON string values. A specially crafted JWK file could exploit this behavior by using integers in places where the code expected a string. This was fixed in v3.3.0. A workaround is available. Users importing keys through a JWK file should not do so from untrusted sources. Use the `jwk2key` tool to check for validity of a JWK file. Likewise, if possible, do not use JWK files with RSA-PSS keys.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-33996 since 03/24/2026. The exploitability is told to be difficult. The attack needs to be done within the local network. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 304156 (Linux Distros Unpatched Vulnerability : CVE-2026-33996), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.3.0 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (304156) and EUVD (EUVD-2026-16899). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• benmcollins

Name

• libjwt

Version

• 3.0
• 3.1
• 3.2

Website

• Product: https://github.com/benmcollins/libjwt/

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