CVE-2026-78438
W3 Total Cache <= 2.10.5 - Unauthenticated Stored Cross-Site Scripting via LazyLoad Background Mutator
CVSS Score
7.2
EPSS Score
0.0%
EPSS Percentile
0th
The W3 Total Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content via LazyLoad Background Mutator in all versions up to, and including, 2.10.5 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 "Lazy Load Images" feature with "Process background images" to be enabled, and the malicious comment to be approved by a moderator before execution is triggered.
| CWE | CWE-79 |
| Vendor | boldgrid |
| Product | w3 total cache |
| Published | Sep 5, 2026 |
| Last Updated | Sep 7, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
Affected Versions
boldgrid / W3 Total Cache
0 ≤ 2.10.5
References
wordfence.com: https://www.wordfence.com/threat-intel/vulnerabilities/id/5580ad05-af50-4899-9cbf-39ad8000eb6a?source=cve plugins.trac.wordpress.org: https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Mutator.php#L293 plugins.trac.wordpress.org: https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Mutator.php#L255 plugins.trac.wordpress.org: https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Mutator.php#L91 plugins.trac.wordpress.org: https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Plugin.php#L87 plugins.trac.wordpress.org: https://plugins.trac.wordpress.org/changeset?reponame=&new=3680101%40w3-total-cache%2Ftags%2F2.10.6&old=3653442%40w3-total-cache%2Ftags%2F2.10.5 plugins.trac.wordpress.org: https://plugins.trac.wordpress.org/changeset?old_path=%2Fw3-total-cache/tags/2.10.5&new_path=%2Fw3-total-cache/tags/2.10.6 plugins.trac.wordpress.org: https://plugins.trac.wordpress.org/changeset/3680101/w3-total-cache/tags/2.10.6/UserExperience_LazyLoad_Mutator.php
Credits
theviper17y