PyJWT: Uncaught RecursionError in jwt.decode() on deeply nested token header — GHSA-8WJV-2P76-3863

Summary

## Package pyjwt (PyPI) ## Affected versions tested & verified on: 2.13.0. Every version whose `PyJWS._load()` translates only `ValueError` is affected ## Description `PyJWS._looad()` (`jwt/api_jws.py:337`) splits the compact token, base64url decodes the header segment and hands it to `json.loads()` before `_verify_signature()` runs. The parse is wrapped in `except ValueError as e: raise DecodeError(...)`. That is…

Timeline

Published by source

2026-09-29

Risk context

• Reported severity or threat level: medium.
• Reported CVSS score: 5.3 out of 10.
• Reported EPSS value: 0.00291.
• Review exposure for the affected product or family: pip: pyJWT.

Product

pip: pyJWT

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

Evidence and provenance

Canonical advisory ID

GHSA-8WJV-2P76-3863

Source

GitHub

Vendor

GitHub

Published by source

2026-09-29

Last source activity

2026-09-29

Additional identifiers

CVE-2026-102265

Curated by

hlukh.ch

Related advisories and connections

These advisories are connected by shared CVE, product, vendor, source, or time signals.