CVE-2026-78438
W3 Total Cache <= 2.10.5 - Unauthenticated Stored Cross-Site Scripting via LazyLoad Background Mutator
Description
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.
INFO
Published Date :
Sept. 5, 2026, 7:17 a.m.
Last Modified :
Sept. 5, 2026, 7:17 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update W3 Total Cache plugin to the latest version.
- Ensure "Lazy Load Images" is configured securely.
- Approve comments only after careful review.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-78438.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-78438 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-78438
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-78438 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-78438 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Sep. 05, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N Added CWE CWE-79 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78438.json">CVE-2026-78438</a> Added Reference https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Mutator.php#L255 Added Reference https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Mutator.php#L293 Added Reference https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Mutator.php#L91 Added Reference https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Plugin.php#L87 Added Reference https://plugins.trac.wordpress.org/changeset/3680101/w3-total-cache/tags/2.10.6/UserExperience_LazyLoad_Mutator.php Added Reference https://plugins.trac.wordpress.org/changeset?old_path=%2Fw3-total-cache/tags/2.10.5&new_path=%2Fw3-total-cache/tags/2.10.6 Added Reference 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 Added Reference https://www.wordfence.com/threat-intel/vulnerabilities/id/5580ad05-af50-4899-9cbf-39ad8000eb6a?source=cve