W3 Total Cache <= 2.9.4 - Unauthenticated Arbitrary File Read via 'f_array[]' Parameter

The W3 Total Cache plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 2.9.4 via the setupSources function. This makes it possible for unauthenticated attackers to read the contents of arbitrary files on the server, which can contain sensitive information. Exploitation requires enabling manual minify mode and supplying a manual-format minify filename so that the hash is empty and the f_array[] entries are not overwritten before reaching setupSources().