Yanni8

**Name of the Vulnerable Software and Affected Versions** PyJWT versions prior to 2.14.0 **Description** The `is pem format()` function is affected by a regular expression issue where lazy PEM processing causes extensive backtracking. This happens when input resembling a certificate contains repeated BEGIN markers but lacks a matching END marker, leading to unbounded backtracking during the search for the end marker. This behavior allows an attacker to cause intensive CPU consumption. **Recommendations** Update to version 2.14.0. As a temporary workaround, restrict the use of the `is pem format()` function when processing untrusted input.