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CVE-2026-48523

5.4 · MEDIUM

PyJWT is a JSON Web Token implementation in Python.

Published May 28, 2026CWE-347EPSS 0.17%

Overview

CVE-2026-48523 is a medium-severity vulnerability. It was published on May 28, 2026 and has a CVSS 3.1 base score of 5.4 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.4, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

Technical description

PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode() or jwt.decode_complete() are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature verification is performed with the algorithm bound to the PyJWK object instead of the header algorithm. An attacker who controls a registered JWK/JWKS private key can sign with a disallowed algorithm, advertise an allowed algorithm in the JWT header, and still be accepted. The issue affects the documented PyJWKClient.get_signing_key_from_jwt(...) flow. This vulnerability is fixed in 2.13.0.

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.

References

GitHubgithub.com/jpadilla/pyjwt/security/advisories/GHSA-jq35-7prp-9v3fGitHubgithub.com/jpadilla/pyjwt/security/advisories/GHSA-jq35-7prp-9v3f

How CyberStrike helps

Frequently asked questions

What is CVE-2026-48523?

CVE-2026-48523 is a medium-severity vulnerability. It was published on May 28, 2026 and has a CVSS 3.1 base score of 5.4 (MEDIUM).

How severe is CVE-2026-48523?

This vulnerability has a CVSS 3.1 base score of 5.4, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2026-48523?

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-2026-48523?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-48523 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.

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