Insufficient verification of data authenticity in pyjwt - CVE-2026-32597

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Main Vulnerability Database Vulnerabilities #VU128143

Insufficient verification of data authenticity in pyjwt - CVE-2026-32597

Published: April 27, 2026


Vulnerability identifier: #VU128143
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-32597
CWE-ID: CWE-345
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to bypass security policy enforcement.

The vulnerability exists due to insufficient verification of data authenticity in the PyJWT token header validation logic when processing JWS tokens with unknown critical header extensions. A remote attacker can send a specially crafted token to bypass security policy enforcement.

This can cause split-brain verification in mixed-library deployments, where other RFC-compliant libraries reject the same token.


Affected software

pyjwt
Debian Linux
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
SUSE Manager Proxy
SUSE Manager Retail Branch Server
SUSE Manager Server
SUSE Linux Enterprise Micro
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Public Cloud Module
SUSE Linux Enterprise Server
SUSE Linux Enterprise Server for SAP Applications
Basesystem Module
Python 3 Module
openSUSE Leap
Ubuntu
openEuler
Anolis OS
IBM Watson Discovery for IBM Cloud Pak for Data
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
pyjwt (Ubuntu package)
python-PyJWT
python3-PyJWT
python3-jwt
python-jwt-help
python-jwt
pyjwt (Debian package)
python3-jwt+crypto
python3-jwt-doc
python311-PyJWT
fence-agents (Red Hat package)

How to mitigate CVE-2026-32597

Install security update from vendor's website.

pyjwt - update to 2.12.0
IBM Watson Discovery for IBM Cloud Pak for Data - update to 5.3.2
pyjwt (Ubuntu package) - addressed in versions 1.3.0-1ubuntu0.1+esm1, 1.5.3+ds1-1ubuntu0.1+esm1, 1.7.1-2ubuntu2.1+esm1, 2.3.0-1ubuntu0.3, 2.7.0-1ubuntu0.1, 2.10.1-2ubuntu0.1
python-PyJWT - update to 1.5.3-3.19.1
python3-PyJWT - addressed in versions 1.5.3-3.19.1, 2.4.0-150200.3.11.1
python3-jwt - update to 2.3.0-5
python-jwt-help - update to 2.3.0-5
python-jwt - update to 2.3.0-5
pyjwt (Debian package) - addressed in versions 2.6.0-1+deb12u1, 2.10.1-2+deb13u1
python3-jwt+crypto - update to 2.6.0-3
python3-jwt-doc - update to 2.6.0-3
python3-jwt - update to 2.6.0-3
python311-PyJWT - update to 2.8.0-150400.8.10.1
fence-agents (Red Hat package) - addressed in versions 4.2.1-129.el8_10.25, 4.10.0-43.el9_2.21, 4.10.0-62.el9_4.24, 4.10.0-98.el9_7.12, 4.16.0-5.el10_0.9, 4.16.0-13.el10_1.4

External References

Related Security Bulletins