CVE-2026-18051: Unknown w3 Total Cache

Critical severity, CVSS 10.0. EPSS: 0.6% chance of exploitation in the next 30 days.

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.

Affected products

• Unknown w3 Total Cache: before 2.10.5 (fixed in 2.10.5)

Published 2026-08-19. Last modified 2026-08-26.