CVE-2026-103001
PyJWT.decode() reintroduces options-dict mutation, enabling silent claim-verification bypass on dict reuse
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.
- Affected
- jpadilla · pyjwt
- CVSS v3.1 GITHUB
- 6.5 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N - EPSS
- 0.24% chance of exploitation in the next 30 days, 14th percentile
- Published
- 2026-09-30
- Updated
- 2026-10-05