Vulnerability · Published Sep 28, 2026 · Assigned by GitHub_M
CVE-2026-102274PyJWT: Malformed RSA JWK aborts parsing of an entire JWK Set
Medium 5.9
In plain English
A medium-severity security flaw in pyjwt from jpadilla. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | pyjwt | no fix listed | DEBIAN-CVE-2026-102274 |
| Debian:13 | pyjwt | no fix listed | DEBIAN-CVE-2026-102274 |
| Debian:14 | pyjwt | 2.14.0-1 | DEBIAN-CVE-2026-102274 |
| PyPI | pyjwt | 2.14.0 | PYSEC-2026-4152 |
| PyPI | pyjwt | 2.14.0 | GHSA-w6j9-cwv2-h6wq |
| Ubuntu:22.04:LTS | pyjwt | 2.3.0-1ubuntu0.6 | USN-8934-1 |
| Ubuntu:22.04:LTS | pyjwt | 2.3.0-1ubuntu0.6 | UBUNTU-CVE-2026-102274 |
| Ubuntu:24.04:LTS | pyjwt | 2.7.0-1ubuntu0.4 | USN-8934-1 |
| Ubuntu:24.04:LTS | pyjwt | 2.7.0-1ubuntu0.4 | UBUNTU-CVE-2026-102274 |
| Ubuntu:26.04:LTS | pyjwt | 2.10.1-4ubuntu1.3 | UBUNTU-CVE-2026-102274 |
| Ubuntu:26.04:LTS | pyjwt | 2.10.1-4ubuntu1.3 | USN-8934-1 |
| Ubuntu:26.10 | pyjwt | 2.13.0-1ubuntu1.1 | USN-8934-1 |
| Ubuntu:26.10 | pyjwt | 2.13.0-1ubuntu1.1 | UBUNTU-CVE-2026-102274 |
Affected products (as reported)
Weakness: CWE-755 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/jpadilla/pyjwt/security/advisories/GHSA-w6j9-cwv2-h6wq x_refsource_CONFIRM
- https://github.com/jpadilla/pyjwt/commit/8915570a0bfda9f0ff0e34e7fb09bdb9d71580cf x_refsource_MISC
- https://github.com/jpadilla/pyjwt/releases/tag/2.14.0 x_refsource_MISC