CVE-2026-102269

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.

CVSS 3.1

5.4CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

EPSS

0.2% chance of exploitation in the next 30 days; higher than 12% of CVEs (scores of 2026-10-25)

CWE

CWE-180

Published

2026-09-28

Modified

2026-10-06

Record from

the NVD, synced 2026-10-19

Affected

• pyjwt_project:pyjwt

Packages (OSV)

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

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