CVE-2026-18051: unknown w3 total cache Path Traversal

Vulnerability summary

CVE-2026-18051 is a critical (CVSS 10.0) Path Traversal vulnerability in unknown w3 total cache. EPSS estimates a 0.57% chance of exploitation in the next 30 days, higher than 46.5% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 2.10.5.

Timeline

1. 19-08-2026
   PublishedVulnerability first disclosed.
2. 19-08-2026
   Last modifiedVulnerability information updated.

Description

The W3 Total Cache WordPress plugin before 2.10.5 does not properly validate the request path it uses 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.

• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.