CVE-2026-102269

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

MEDIUM
5.4
CVSS Score
Published: September 28, 2026 at 08:27 PM UTC
Updated: October 6, 2026 at 06:54 PM UTC
2 products affected across 2 vendorsPyjwtPyjwt

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.2%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.14.0
Affected range stops below 2.14.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/jpadilla/pyjwt/security/advisories/GHSA-hxm8-2xgr-2p9m
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/jpadilla/pyjwt/releases/tag/2.14.0

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-180

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