Improper Verification of Cryptographic Signature in pyjwt - CVE-2026-48523

Vulnerability identifier: #VU132100

CSH Severity: Low

CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-48523

CWE-ID: CWE-347

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote user to bypass algorithm policy enforcement.

The vulnerability exists due to improper verification of cryptographic signature in the PyJWK verification path when decoding JWTs with PyJWK or PyJWKClient-derived keys. A remote user can sign a token with a disallowed algorithm while advertising an allowed algorithm in the JWT header to bypass algorithm policy enforcement.

Exploitation requires control of a registered JWK or JWKS private key, such as in multi-tenant or federation-style trust models.

pyjwt
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
SUSE Manager Server
SUSE Manager Retail Branch Server
SUSE Manager Proxy
SUSE Linux Enterprise Micro
SUSE Linux Micro
Public Cloud Module
Python 3 Module
Basesystem Module
openSUSE Leap
IBM Cloud Pak for Data System
IBM Watson Discovery for IBM Cloud Pak for Data
python3-PyJWT
python311-PyJWT

Install security update from vendor's website.

pyjwt - update to 2.13.0
IBM Cloud Pak for Data System - update to 8.10.26.06.SP2
IBM Watson Discovery for IBM Cloud Pak for Data - update to 5.3.2
python3-PyJWT - update to 2.4.0-150200.3.14.1
python311-PyJWT - addressed in versions 2.8.0-150400.8.13.1, 2.12.1-slfo.1.1_2.1

• https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jq35-7prp-9v3f

• Multiple vulnerabilities in pyjwt
• SUSE update for python-PyJWT
• Multiple vulnerabilities in IBM Watson Discovery Cartridge
• SUSE update for python-PyJWT
• SUSE update for python-PyJWT
• Multiple vulnerabilities in IBM Cloud Pak for Data System