Unintended Proxy or Intermediary ('Confused Deputy') Affecting python313-PyJWT package, versions <2.12.1-160000.2.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.22% (13th percentile)

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  • Snyk IDSNYK-SLES1600-PYTHON313PYJWT-17439530
  • published24 Jun 2026
  • disclosed19 Jun 2026

Introduced: 19 Jun 2026

CVE-2026-48522  (opens in a new tab)
CWE-441  (opens in a new tab)
CWE-918  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 python313-PyJWT to version 2.12.1-160000.2.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python313-PyJWT package and not the python313-PyJWT package as distributed by SLES. See How to fix? for SLES:16.0.0 relevant fixed versions and status.

PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, PyJWKClient passes its uri argument directly to urllib.request.urlopen() which uses Python stdlib's default OpenerDirector registering HTTPHandler, HTTPSHandler, FTPHandler, FileHandler, and DataHandler. There is currently no documented option to restrict which schemes PyJWKClient will fetch. If an application's jku URL ingestion path accepts attacker-influenced URLs (e.g., from JWT header, configuration file, OAuth flow parameter), the attacker can cause PyJWKClient to read arbitrary local files via file:// (SSRF on local filesystem), cause PyJWKClient to attempt FTP / data-URI fetches (broader SSRF surface), or forge tokens that PyJWT verifies as valid. The library does not directly return non-HTTP(S) URI contents to the attacker; the chained "plant a JWKS to forge tokens" scenario described in the original report requires additional application-layer flaws (attacker write access to a filesystem path, untrusted jku derivation) that this fix does not address. This vulnerability is fixed in 2.13.0.

CVSS Base Scores

version 3.1