What’s Vulnerable › Vulnerabilities

CVE-2026-102269: PyJWT: Non-canonical signature segments enable raw-token revocation bypass

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-09-28 · updated 2026-10-06
• Weakness: CWE-180

Description

PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT signature segment is affected because signature segment decoding accepts characters outside the canonical Base64URL representation. This occurs when non-Base64URL characters are appended to a valid compact JWS signature segment. As a result, base64url_decode produces the same signature bytes for different serialized segments. Consequently, raw-token revocation checks can fail to recognize an equivalent modified token. This issue is fixed in version 2.14.0.

Affected products

• jpadilla pyjwt: 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/e6f48401001609a8f99e71fcaf355fb895d508a8
• https://github.com/jpadilla/pyjwt/releases/tag/2.14.0
• https://github.com/jpadilla/pyjwt/security/advisories/GHSA-hxm8-2xgr-2p9m

Get alerted when CVE-2026-102269 or the next vulnerability affects your stack