# CVE-2026-103001: PyJWT.decode() reintroduces options-dict mutation, enabling silent claim-verification bypass on dict reuse

CVE-2026-103001 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-103001, released October 4, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-103001
- Priority: Routine
- CVSS: 6.5 (Moderate)
- EPSS: 0.0026
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 30, 2026
- Weakness: Modification of Assumed-Immutable Data (MAID)
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-103001

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | pyjwt Debian 14 | 2.14.0-1 | [DEBIAN-CVE-2026-103001](https://patchblox.com/security/data/fix/linux/debian-cve-2026-103001.md) | Oct 4, 2026 |
| Linux | python-PyJWT opensuse-leap 16.0 | 2.12.1-160000.3.1 | [OPENSUSE-SU-2026:22074-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22074-1.md) | Nov 7, 2026 |
| Linux | python-PyJWT sles 16.0 | 2.12.1-160000.3.1 | [SUSE-SU-2026:24219-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24219-1.md) | Nov 7, 2026 |

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Data as of 2026-11-10T07:50:38Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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