What’s Vulnerable › Vulnerabilities

CVE-2026-102274: PyJWT: Malformed RSA JWK aborts parsing of an entire JWK Set

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-09-28 · updated 2026-10-06
• Weakness: CWE-755

Description

PyJWT is a Python implementation of JSON Web Token standards. From 2.9.0 until 2.14.0, PyJWKSet does not catch the plain ValueError raised for malformed RSA JWK components by RSAAlgorithm.from_jwk in jwt/api_jwk.py. This occurs when a JWK Set contains a malformed RSA key alongside otherwise usable keys. As a result, one malformed member aborts construction of the entire PyJWKSet. Consequently, applications can experience authentication failures or request-level denial of service. This issue is fixed in version 2.14.0.

Affected products

• jpadilla pyjwt: from 2.9.0 before 2.14.0 — fixed in 2.14.0

How to fix

Upgrade to a fixed version: jpadilla pyjwt 2.14.0. Check the vendor advisory for mitigations.

References

• https://github.com/jpadilla/pyjwt/commit/8915570a0bfda9f0ff0e34e7fb09bdb9d71580cf
• https://github.com/jpadilla/pyjwt/releases/tag/2.14.0
• https://github.com/jpadilla/pyjwt/security/advisories/GHSA-w6j9-cwv2-h6wq
• https://github.com/jpadilla/pyjwt/security/advisories/GHSA-w6j9-cwv2-h6wq

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