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High severity · published Aug 14, 2026
CVE-2026-18109
W3 Total Cache <= 2.10.3 - Unauthenticated Stored Cross-Site Scripting via Comment Author Name
7.2
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WT
W3 Total Cache · boldgrid
through 2.10.3 · source: vendor
Affected product
WT
W3 Total Cache
boldgrid
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-18109
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-18109
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.2/UserExperience_LazyLoad_Mutator.php#L162
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.2/UserExperience_LazyLoad_Mutator.php#L403
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.2/UserExperience_LazyLoad_Mutator.php#L85
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.2/UserExperience_LazyLoad_Plugin.php#L116
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/changeset/3635675/w3-total-cache/trunk/UserExperience_LazyLoad_Mutator.php
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/changeset?old_path=%2Fw3-total-cache/tags/2.10.3&new_path=%2Fw3-total-cache/tags/2.10.4
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