CVE-2026-78438
HighCVSS 7.2Exploitation Probability (EPSS)
Low risk21th percentile - higher than 21% of all known CVEs
Summary
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.
Risk Assessment
The risk includes execution of malicious scripts in the user's browser, potentially leading to session theft, account takeover, or malware distribution.
Recommendation
It is recommended to update the plugin to the latest patched version and implement proper sanitization and output escaping for comment content.
Other vulnerabilities in W3 Total Cache
See all- CVE-2026-39595Medium
W3 Total Cache versions up to 2.9.1 contain a broken access control vulnerability, potentially allowing unauthorized access to resources.
- CVE-2026-18051Critical
The W3 Total Cache WordPress plugin before 2.10.5 does not properly validate the request path used to build cache file names, allowing unauthenticated attackers to write a file into any existing directory on the server, inside or outside the web root, overwriting whatever occupies the target name. On Apache, the same flaw overwrites the site's .htaccess files, which breaks the site and can strip hardening rules that other security measures rely on.
- CVE-2026-57623Critical
The W3 Total Cache plugin versions up to 2.9.4 contain a critical vulnerability allowing unauthenticated remote arbitrary code execution. The flaw stems from insufficient input validation in the caching mechanism.
- CVE-2026-18109High
The W3 Total Cache plugin for WordPress up to version 2.10.3 is vulnerable to Stored Cross-Site Scripting via Comment Author Name due to insufficient input sanitization and output escaping. The vulnerability is only exploitable when the Lazy Load Images feature is enabled, as the unsafe re-emission occurs exclusively within the LazyLoad mutator's img tag rewriting step.
- CVE-2026-66695Medium
Path Traversal vulnerability in W3 Total Cache versions up to 2.10.2 allows an unauthenticated attacker to access files outside the root directory.
- CVE-2026-9282High
The W3 Total Cache plugin for WordPress up to version 2.9.4 is vulnerable to Directory Traversal via the setupSources function. Unauthenticated attackers can read arbitrary files on the server, potentially exposing sensitive information. Exploitation requires enabling manual minify mode and providing a specific minify filename.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS