Disclosure summary
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.
Source-reported weakness categories
CWE-471
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
NIST National Vulnerability Database · NVD-CVE-2026-103001
Open original source · Updated Oct 05, 2026
Only CPE matches marked vulnerable=true are indexed. AND/OR platform conditions must be checked in the original NVD record.
GitHub Reviewed Security Advisories · GHSA-gvp8-978c-rx2q
Open original source · Updated Sep 30, 2026
PyJWT.decode() reintroduces options-dict mutation, enabling silent claim-verification bypass on dict reuse
Source severity: MEDIUM / 0
| Ecosystem | Package | Affected range | First patched |
|---|---|---|---|
| pip | PyJWT | >= 2.11.0, | Not supplied |
Original records & references
PUBLISHED 2026-09-30T18:16:33-04:00
MODIFIED 2026-10-05T20:16:32-04:00
INGESTED 2026-10-06T11:45:14-04:00