CVE-2026-16778
Received Received - Intake

Stored XSS in Live Composer WordPress Plugin

Publication date: 2026-09-22

Last updated on: 2026-09-22

Assigner: Wordfence

Description
The Live Composer – Free WordPress Website Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'dslc_module_downloads_output' Shortcode Content in all versions up to, and including, 2.1.21 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The save-time wp_kses_post check is bypassed because the payload is stored as a serialized string containing no HTML tags for kses to tokenize, and the shortcode callback re-emits attacker-controlled values — including view_all_link (href attribute), main_heading_title (h2 body), button_text (anchor body), and button_inline_svg (anchor body) — without any escaping at render time.

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Meta Information

Published
2026-09-22
Last Modified
2026-09-22
Generated
2026-09-22
AI Q&A
2026-09-22
EPSS Evaluated
N/A
NVD
CVE-2026-16778
EUVD
EUVD-2026-84298

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
live_composer free_wordpress_website_builder to 2.1.21 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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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.

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Executive Summary

This is a Stored Cross-Site Scripting (XSS) vulnerability in the Live Composer WordPress plugin up to version 2.1.21. It allows authenticated attackers with contributor-level access or higher to inject malicious scripts into web pages via the 'dslc_module_downloads_output' shortcode. The vulnerability bypasses WordPress's wp_kses_post sanitization by storing payloads as serialized strings without HTML tags. When rendered, the plugin outputs attacker-controlled values like links and text without proper escaping, enabling script execution.

Detection Guidance

To detect this vulnerability, inspect WordPress sites using the Live Composer plugin for versions up to 2.1.21. Check for unauthorized script injections in pages via the 'dslc_module_downloads_output' shortcode. Review contributor-level user activity logs for suspicious edits. Use WordPress security plugins to scan for stored XSS payloads in serialized strings.

Impact Analysis

An attacker could steal user sessions, redirect visitors to malicious sites, or deface your website. Since it requires contributor access, it primarily affects sites where untrusted users can publish content. The impact includes potential data theft, malware distribution, or reputational damage from compromised pages.

Compliance Impact

This vulnerability could lead to unauthorized data access or modification, violating GDPR's integrity and confidentiality principles or HIPAA's safeguards for protected health information. If exploited, it may result in data breaches requiring regulatory notifications and potential fines under these standards.

Mitigation Strategies

Update the Live Composer plugin to the latest version beyond 2.1.21. Remove or disable the plugin if updates are unavailable. Review WordPress user roles to ensure only trusted users have contributor-level access or higher.

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