Vulnerability Details CVE-2026-102270
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT is_pem_format is affected because lazy PEM regular expression backtracks extensively. This occurs when a certificate-like input contains repeated BEGIN markers without a matching END marker. As a result, is_pem_format performs unbounded backtracking while searching for a PEM end marker. Consequently, an attacker can cause intensive CPU consumption. This issue is fixed in version 2.14.0.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 8.0%
CVSS Severity
CVSS v3 Score 4.4