Read the docs
TI-2026-35882 Aliases CVE-2026-48522GHSA-993g-76c3-p5m4

PyJWKClient: missing scheme allowlist enables SSRF + token forgery via file://, ftp://, data: schemes

Priority MEDIUM 53CWE-441Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Partial Red Hat: 13 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00222 12th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial pyjwt (jpadilla): 2.13.0PyJWT (PyPI): 2.13.0Red Hat: 13 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
jpadillapyjwtbefore 2.13.02.13.0Patch availableCNA
—PyJWT (PyPI)2.0.0 to before 2.13.02.13.0Patch availableGHSA-993g-76c3-p5m4
  • pyjwt Vendorjpadilla Affected before 2.13.0 Fixed in 2.13.0 Patch available CNA
  • PyJWT (PyPI) Vendor— Affected 2.0.0 to before 2.13.0 Fixed in 2.13.0 Patch available GHSA-993g-76c3-p5m4

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:*before 2.13.0Vulnerablejpadilla
  • cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:* Versions before 2.13.0 Vulnerable ·jpadilla

Remediation

  • Fix · CNA pyjwt (jpadilla) Fixed in 2.13.0
  • Fix · GHSA-993g-76c3-p5m4 PyJWT (PyPI) Fixed in 2.13.0 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Migration Toolkit for Applications 8AffectedNo fix yet: Fix deferred
OpenShift LightspeedAffectedNo fix yet: Fix deferred
Red Hat AI Inference ServerAffectedNo fix yet: Fix deferred
Red Hat Ansible Automation Platform 2AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix yet: Fix deferred
Red Hat Hardened ImagesAffectedNo fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet: Fix deferred
Red Hat Quay 3AffectedNo fix yet: Fix deferred
Red Hat Satellite 6AffectedNo fix yet: Fix deferred
Red Hat Trusted Artifact SignerAffectedNo fix yet: Fix deferred
Red Hat Update Infrastructure 4 for Cloud ProvidersAffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-48522
  2. 2026-10-03 Alias added: GHSA-993g-76c3-p5m4
  3. 2026-10-16 Affected versions changed · Red Hat

References

Exploit 1

Advisory 1

Other 3

  • TI-2026-65303 Improper signature verification in jpadilla pyjwt CVSS 3.1CRITICAL 9.1
  • TI-2026-65301 PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation CVSS 3.1CRITICAL 9.1
  • TI-2026-65219 PyJWT: Unauthenticated RecursionError DoS in pre-verification payload parse… CVSS 3.1HIGH 7.5
  • TI-2026-65218 PyJWT: PyJWKClient still amplifies unauthenticated JWKS fetches on unknown kid values (incomplete fix of CVE-2026-48524) CVSS 3.1HIGH 7.5
  • TI-2026-25107 PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation) CVSS 3.1HIGH 7.5
  • TI-2026-65310 PyJWT accepts inconsistent OKP x/d JWKs, causing public/private key identity confusion CVSS 3.1HIGH 8.2
See all 23 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences