CMSimple_XH 1.7.4 contains an authenticated remote code execution vulnerability in the content editing functionality that allows administrative users to upload malicious PHP files. Attackers with valid credentials can exploit the CSRF token mechanism to create a PHP shell file that enables arbitrary command execution on the server.
A reflected XSS vulnerability exists in CMSimple_XH 1.8's index.php router when attacker-controlled path segments are not sanitized or encoded before being inserted into the generated HTML (navigation links, breadcrumbs, search form action, footer links). An attacker-controlled string placed in the URL path is reflected into multiple HTML elements, allowing execution of arbitrary JavaScript in victims' browsers visiting a crafted URL.
An unauthenticated reflected cross-site scripting vulnerability in the query handling of CMSimpleXH allows remote attackers to inject and execute arbitrary JavaScript in a victim's browser via a crafted request (e.g., a maliciously crafted POST login). Successful exploitation may lead to theft of session cookies, credential disclosure, or other client-side impacts.