Two very popular WordPress caching plugins (WP Super Cache and W3 Total Cache) are vulnerable to PHP code execution via interpretation of dynamic snippets, that are contained inside a number of specific HTML-comment tags. WP Super Cache (before version 1.3) and W3 Total Cache (before version 0.9.2.9) are vulnerable to this issue.
Remote PHP code execution.
Upgrade the vulnerable plugin(s) to the latest version.
WP Caching plugin vulnerability debrief
WP Super Cache
W3 Total Cache
Initial report of the vulnerability