Medium severity · published Sep 28, 2026
CVE-2026-102269
PyJWT: Non-canonical signature segments enable raw-token revocation bypass
5.4
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 13% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PY
pyjwt · jpadilla
< 2.14.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-102269
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-102269
x_refsource_CONFIRM
https://github.com/jpadilla/pyjwt/security/advisories/GHSA-hxm8-2xgr-2p9m
x_refsource_MISC
https://github.com/jpadilla/pyjwt/commit/e6f48401001609a8f99e71fcaf355fb895d508a8
x_refsource_MISC
https://github.com/jpadilla/pyjwt/releases/tag/2.14.0
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