Vulnerability in WP Fastest Cache – WordPress Cache Plugin — CVE-2026-19760

What to do now

Update WP Fastest Cache – WordPress Cache Plugin to 1.5.1 or later.

Affected versions

• Everything up to and including 1.5.0

The WP Fastest Cache – WordPress Cache Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via HTTP Host Header in all versions up to, and including, 1.5.0 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 Polylang or Polylang Pro plugin to be active and the Combine JS option to be enabled, as these conditions trigger the vulnerable Host-header-to-URL code path that writes attacker-controlled script src values into the shared page-cache file served to all subsequent visitors.

This description is reproduced verbatim from the public vulnerability record.

• https://plugins.trac.wordpress.org/browser/wp-fastest-cache/tags/1.4.9/inc/js-utilities.php#L257
• https://plugins.trac.wordpress.org/browser/wp-fastest-cache/tags/1.4.9/inc/js-utilities.php#L274
• https://plugins.trac.wordpress.org/browser/wp-fastest-cache/tags/1.4.9/wpFastestCache.php#L507
• https://plugins.trac.wordpress.org/browser/wp-fastest-cache/tags/1.5.0/inc/js-utilities.php#L257
• https://plugins.trac.wordpress.org/browser/wp-fastest-cache/tags/1.5.0/inc/js-utilities.php#L274
• https://plugins.trac.wordpress.org/browser/wp-fastest-cache/tags/1.5.0/wpFastestCache.php#L507

This page is compiled automatically from public databases. Accuracy is not guaranteed; confirm against the vendor advisory before acting.