PyJWT is a Python implementation of JSON Web Token standards. From 2.11.0 through 2.13.0, PyJWT's PyJWT._merge_options() method can modify a caller-supplied mutable options mapping when verify_signature is false. If an application reuses that same mapping for a later decode() or decode_complete() call and changes verify_signature to true, the mapping can retain false values for expiration, not-before, issued-at, audience, issuer, subject, and JWT ID checks. A signed token with invalid registered claims can then be accepted without disabling signature verification, but applications that create a fresh options mapping for each call are not affected.
History

Thu, 08 Oct 2026 13:30:00 +0000

Type Values Removed Values Added
First Time appeared Pyjwt Project
Pyjwt Project pyjwt
CPEs cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:*
Vendors & Products Pyjwt Project
Pyjwt Project pyjwt

Tue, 06 Oct 2026 00:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 01 Oct 2026 06:00:00 +0000

Type Values Removed Values Added
First Time appeared Jpadilla
Jpadilla pyjwt
Vendors & Products Jpadilla
Jpadilla pyjwt

Thu, 01 Oct 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-358
References
Metrics threat_severity

None

threat_severity

Moderate


Wed, 30 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Description PyJWT is a Python implementation of JSON Web Token standards. From 2.11.0 through 2.13.0, PyJWT's PyJWT._merge_options() method can modify a caller-supplied mutable options mapping when verify_signature is false. If an application reuses that same mapping for a later decode() or decode_complete() call and changes verify_signature to true, the mapping can retain false values for expiration, not-before, issued-at, audience, issuer, subject, and JWT ID checks. A signed token with invalid registered claims can then be accepted without disabling signature verification, but applications that create a fresh options mapping for each call are not affected.
Title PyJWT.decode() reintroduces options-dict mutation, enabling silent claim-verification bypass on dict reuse
Weaknesses CWE-471
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-09-30T21:15:12.862Z

Updated: 2026-10-05T23:47:32.912Z

Reserved: 2026-09-29T20:46:08.335Z

Link: CVE-2026-103001

cve-icon Vulnrichment

Updated: 2026-10-05T23:47:27.875Z

cve-icon NVD

Status : Analyzed

Published: 2026-09-30T22:16:33.537

Modified: 2026-10-08T13:13:53.857

Link: CVE-2026-103001

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-30T21:15:12Z

Links: CVE-2026-103001 - Bugzilla