The vulnerability description explicitly states that the plugin 'evaluates part of a URL as code,' which strongly suggests unvalidated/unescaped URL input is incorporated into the server's response. In Jenkins plugins, this typically occurs in HTTP request handling methods (e.g., doGet, doDynamic, or custom actions) that process URL parameters/paths and generate dynamic content. The lack of output encoding or sanitization in these methods leads to reflected XSS. While the exact function name/path isn't provided in the advisories, the pattern matches common Jenkins plugin vulnerability patterns.