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.
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History
Thu, 08 Oct 2026 13:30:00 +0000
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Pyjwt Project
Pyjwt Project pyjwt |
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| CPEs | cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Pyjwt Project
Pyjwt Project pyjwt |
Tue, 06 Oct 2026 00:30:00 +0000
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ssvc
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Thu, 01 Oct 2026 06:00:00 +0000
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Jpadilla
Jpadilla pyjwt |
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| Vendors & Products |
Jpadilla
Jpadilla pyjwt |
Thu, 01 Oct 2026 00:15:00 +0000
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| Weaknesses | CWE-358 | |
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threat_severity
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threat_severity
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Wed, 30 Sep 2026 21:30:00 +0000
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| 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 |
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| Metrics |
cvssV3_1
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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
Updated: 2026-10-05T23:47:27.875Z
Status : Analyzed
Published: 2026-09-30T22:16:33.537
Modified: 2026-10-08T13:13:53.857
Link: CVE-2026-103001