CVE-2026-18109

W3 Total Cache versions up to 2.9.1 contain a broken access control vulnerability, potentially allowing unauthorized access to resources.

The W3 Total Cache WordPress plugin before 2.10.5 does not properly validate the request path used to build cache file names, allowing unauthenticated attackers to write a file into any existing directory on the server, inside or outside the web root, overwriting whatever occupies the target name. On Apache, the same flaw overwrites the site's .htaccess files, which breaks the site and can strip hardening rules that other security measures rely on.

The W3 Total Cache plugin versions up to 2.9.4 contain a critical vulnerability allowing unauthenticated remote arbitrary code execution. The flaw stems from insufficient input validation in the caching mechanism.

The W3 Total Cache WordPress plugin before 2.10.6 does not confine a media-import file copy to the document root, nor enforce an effective file-type restriction on it, allowing users with the Author role or higher to plant content that, once an administrator runs the import, copies an arbitrary server-readable file into a publicly served directory, exposing it to unauthenticated retrieval.

The W3 Total Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content via Output-Buffer Regex Rewrite in all versions up to, and including, 2.10.6 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This vulnerability is only exploitable when the 'Remove query strings from static resources' option is enabled in W3 Total Cache.

The W3 Total Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content via LazyLoad Background Mutator in all versions up to, and including, 2.10.5 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the "Lazy Load Images" feature with "Process background images" to be enabled, and the malicious comment to be approved by a moderator before execution is triggered.

Path Traversal vulnerability in W3 Total Cache versions up to 2.10.2 allows an unauthenticated attacker to access files outside the root directory.

The W3 Total Cache plugin for WordPress up to version 2.9.4 is vulnerable to Directory Traversal via the setupSources function. Unauthenticated attackers can read arbitrary files on the server, potentially exposing sensitive information. Exploitation requires enabling manual minify mode and providing a specific minify filename.