CVE-2026-18109: W3 Total Cache <= 2.10.3 - Unauthenticated Stored Cross-Site Scripting via Comment Author Name
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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-18109?
CVE-2026-18109 has a high severity rating of 7.2.
How do I fix CVE-2026-18109?
To fix CVE-2026-18109, update the W3 Total Cache plugin to version 2.10.4 or later.
What type of vulnerability is CVE-2026-18109?
CVE-2026-18109 is an Unauthenticated Stored Cross-Site Scripting (XSS) vulnerability.
Who can exploit CVE-2026-18109?
Unauthenticated attackers can exploit CVE-2026-18109 to inject arbitrary web scripts.
Which software is affected by CVE-2026-18109?
CVE-2026-18109 affects the W3 Total Cache plugin for WordPress in all versions up to and including 2.10.3.