CVE-2026-18109
Received Received - Intake

Stored XSS in W3 Total Cache WordPress Plugin

Publication date: 2026-08-14

Last updated on: 2026-08-14

Assigner: Wordfence

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 Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-08-14
Last Modified
2026-08-14
Generated
2026-08-14
AI Q&A
2026-08-14
EPSS Evaluated
N/A
NVD
CVE-2026-18109
EUVD
EUVD-2026-58570

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
wordpress w3_total_cache to 2.10.3 (inc)

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This is a Stored Cross-Site Scripting (XSS) vulnerability in the W3 Total Cache WordPress plugin up to version 2.10.3. It occurs due to insufficient input sanitization and output escaping in the Comment Author Name field. Unauthenticated attackers can inject malicious scripts into pages, which execute when users access those pages. Exploitation requires the Lazy Load Images feature to be enabled.

Detection Guidance

Check if the W3 Total Cache plugin is installed and its version is up to 2.10.3. Verify if the Lazy Load Images feature is enabled in the plugin settings. Inspect WordPress comment sections for unusual scripts in author names.

Impact Analysis

An attacker could steal user sessions, redirect users to malicious sites, or perform actions on their behalf. It may also deface websites or spread malware. Users with admin access could have their credentials compromised, leading to full site takeover.

Compliance Impact

This vulnerability could lead to unauthorized data access or modification, violating GDPR's data protection requirements or HIPAA's security rules for protected health information. Organizations may face fines or legal penalties for non-compliance if user data is compromised through this flaw.

Mitigation Strategies

Update the W3 Total Cache plugin to the latest version beyond 2.10.3. Disable the Lazy Load Images feature if enabled. Review and remove any suspicious scripts from comments.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-18109. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart