CVE-2026-44699
LibJWT is a C JSON Web Token Library.
Overview
CVE-2026-44699 is a known-severity vulnerability. It was published on May 15, 2026.
Technical description
LibJWT is a C JSON Web Token Library. From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the verification key for an HS256/HS384/HS512 token. In the OpenSSL backend, this causes HMAC verification to run with a zero-length key, so an attacker can forge a valid JWT without knowing any secret or RSA private key. This is an algorithm-confusion authentication bypass. It affects applications that load RSA keys from JWKS where alg is omitted, which is valid JWK syntax and common in real deployments, and then choose the verification algorithm from the JWT header, for example in a kid lookup callback. This vulnerability is fixed in 3.3.3.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2026-44699?
CVE-2026-44699 is a known-severity vulnerability. It was published on May 15, 2026.
How severe is CVE-2026-44699?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-44699?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-44699?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-44699 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.