CVE-2026-102269CWE-180

CVE-2026-102269

Medium · published September 29, 2026

CVSS v3.1
4.8
EPSS
0%
Percentile
8.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
4.8 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00191 · 8.3th percentile
Weakness
CWE-180 · Incorrect Behavior Order: Validate Before Canonicalize
Published
2026-09-29T01:17Z
Affected products (1)
ProductVersionsFixed in
pyjwt_project/pyjwt< 2.14.02.14.0
References (3)
https://github.com/jpadilla/pyjwt/commit/e6f48401001609a8f99e71fcaf355fb895d508a8 · [email protected]https://github.com/jpadilla/pyjwt/releases/tag/2.14.0 · [email protected]https://github.com/jpadilla/pyjwt/security/advisories/GHSA-hxm8-2xgr-2p9m · [email protected]
EPSS history
Timeline
  • 30 SEP 03:24Z
    EPSS moved — → 0%
    epss
  • 28 SEP 20:27Z
    PyJWT: Non-canonical signature segments enable raw-token revocation bypass
    cvelistv5