Inefficient regular expression complexity in pyjwt - CVE-2026-102270

Vulnerability identifier: #VU158759

CSH Severity: Low

CVSS v4: 5.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-102270

CWE-ID: CWE-1333

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote privileged user to cause a denial of service through excessive CPU consumption.

The vulnerability exists due to inefficient regular expression complexity in PyJWT's is_pem_format function when processing attacker-controlled key or certificate bytes during key preparation. A remote privileged user can supply malformed PEM-like input containing repeated -----BEGIN CERTIFICATE----- lines without a matching end marker to trigger repeated regular expression rescans with quadratic runtime and exhaust CPU resources.

pyjwt
SUSE Linux Enterprise Server 15 SP6
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SUSE Linux Enterprise Server 15 SP5
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SUSE Linux Enterprise High Performance Computing 15
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SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Desktop 15
SUSE Manager Proxy
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Public Cloud Module
Python 3 Module
openSUSE Leap
python311-PyJWT

Install security update from vendor's website.

pyjwt - update to 2.14.0
python311-PyJWT - update to 2.8.0-150400.8.20.1

• https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jwrc-g2q2-pq5p

• Multiple vulnerabilities in pyjwt
• SUSE update for python-PyJWT