Update the WordPress WP Super Cache plugin to the latest available version (at least 1.7.2).
Vlad Vector discovered and reported this Remote Code Execution (RCE) vulnerability in WordPress WP Super Cache Plugin. This could allow a malicious actor to execute commands on the target website. This can be used to gain backdoor access to then take full control of the website. This vulnerability has been fixed in version 1.7.2.
Cache Poisoning vulnerability
Authenticated Persistent CrossSite Scripting (XSS) vulnerability
Cross Site Scripting
PHP Object Injection