Executive brief
W3 Total Cache, a popular WordPress plugin used to improve website performance, contains a security flaw that allows unauthorized individuals to view private files on the web server. By exploiting this vulnerability, an attacker could read sensitive configuration files or system data, potentially leading to a full site compromise. This issue affects websites where the 'manual minify' feature is enabled.
Technical details
A directory traversal vulnerability exists in the W3 Total Cache plugin for WordPress due to insufficient input validation in the setupSources() function within the Minify component. An unauthenticated remote attacker can exploit this by enabling manual minify mode and providing a specially crafted manual-format minify filename. If the filename results in an empty hash, the f_array[] entries are not overwritten, allowing the attacker to traverse directories and read arbitrary files on the server. The vulnerability is present in versions up to 2.9.4 and has been addressed in subsequent updates.
Affected products
- BoldGrid W3 Total Cache up to, and including, 2.9.4
Timeline
- 2026-07-11: disclosed
- 2026-07-11: advisory
References
- https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.9.4/Minify_MinifiedFileRequestHandler.php
- https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.9.4/Minify_Plugin.php
- https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.9.4/lib/Minify/Minify/Controller/MinApp.php
- https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.9.4/lib/Minify/Minify/Controller/MinApp.php
- https://plugins.trac.wordpress.org/changeset?reponame=&old=3585227%40w3-total-cache&new=3585227%40w3-total-cache
- https://www.wordfence.com/threat-intel/vulnerabilities/id/e92cc06d-006f-4bba-a4ef-b23d80c00085?source=cve