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

Medium · CVSS 6.5CVE-2026-103001GHSA-GVP8-978C-RX2Q

PyJWT.decode() reintroduces options-dict mutation, enabling silent claim-verification bypass on dict reuse

Answer in brief

CVE-2026-103001 records a Medium severity (CVSS 6.5) vulnerability in PyJWT.decode() reintroduces options-dict mutation, enabling silent claim-verification bypass on dict reuse. The current sources do not mark it as known exploited. The current feed maps jpadilla/pyjwt (generic), PyJWT (pip), pyjwt (pypi). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 30, 2026Updated Oct 1, 2026Source checked Oct 1, 2026First seen by HOL Sep 30, 2026Material review Oct 1, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.5
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Not reported

Why this deserves its current priority

CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps jpadilla/pyjwt (generic), PyJWT (pip), pyjwt (pypi). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
jpadilla/pyjwtgeneric	>=2.11.0 <=2.13.0	Not reported
PyJWTpip	>=2.11.0,<=2.13.0	Not reported
pyjwtpypi	>=2.11.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for jpadilla/pyjwt, PyJWT, pyjwt.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 30, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.