CVE-2026-18109

high

Description

The W3 Total Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Author Name in all versions up to, and including, 2.10.3 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 Lazy Load Images feature of W3 Total Cache is enabled, as the unsafe re-emission occurs exclusively within the LazyLoad mutator's img tag rewriting step.

References

https://www.wordfence.com/threat-intel/vulnerabilities/id/16ac73ae-6a0a-4c9b-8830-e0745061e587?source=cve

https://plugins.trac.wordpress.org/changeset?reponame=&new=3635675%40w3-total-cache%2Ftags%2F2.10.4&old=3625062%40w3-total-cache%2Ftags%2F2.10.3

https://plugins.trac.wordpress.org/changeset?old_path=%2Fw3-total-cache/tags/2.10.3&new_path=%2Fw3-total-cache/tags/2.10.4

https://plugins.trac.wordpress.org/changeset/3635675/w3-total-cache/trunk/UserExperience_LazyLoad_Mutator.php

https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.2/UserExperience_LazyLoad_Plugin.php#L116

https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.2/UserExperience_LazyLoad_Mutator.php#L85

https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.2/UserExperience_LazyLoad_Mutator.php#L403

https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.2/UserExperience_LazyLoad_Mutator.php#L162

Details

Source: Mitre, NVD

Published: 2026-08-14

Updated: 2026-08-14

Risk Information

CVSS v2

Base Score: 6.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 7.2

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Severity: High