CVE-2026-0736 in Chatbot Plugin
Summary
by MITRE • 02/14/2026
The Chatbot for WordPress by Collect.chat plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the '_inpost_head_script[synth_header_script]' post meta field in all versions up to, and including, 2.4.8 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.
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Analysis
by VulDB Data Team • 02/20/2026
The vulnerability identified as CVE-2026-0736 resides within the Chatbot for WordPress plugin developed by Collect.chat, affecting all versions through 2.4.8. This represents a critical security flaw that exploits the plugin's inadequate handling of user input within the WordPress ecosystem. The vulnerability specifically targets the '_inpost_head_script[synth_header_script]' post meta field, which serves as an entry point for malicious code injection. Security researchers have classified this issue as a stored cross-site scripting vulnerability, indicating that malicious scripts persist in the application's database and execute whenever affected pages are accessed.
The technical flaw stems from insufficient input sanitization and output escaping mechanisms within the plugin's codebase. When administrators or users with Contributor-level privileges and above create or modify posts, they can inject malicious JavaScript code into the specified meta field. This code then gets stored in the WordPress database and executed in the context of any user's browser who accesses pages containing the malicious content. The vulnerability does not require complex exploitation techniques or special privileges beyond those already granted to the attacker's role, making it particularly dangerous in environments where multiple users have varying levels of access. The flaw directly violates security principles established in the OWASP Top Ten, specifically addressing the category of cross-site scripting vulnerabilities.
The operational impact of this vulnerability extends beyond simple script execution, potentially enabling attackers to perform a wide range of malicious activities. Authenticated attackers can leverage this vulnerability to steal user sessions, redirect visitors to malicious websites, deface content, or even escalate privileges within the WordPress installation. The stored nature of the vulnerability means that the malicious code remains persistent, continuously affecting any user who accesses affected pages until the vulnerability is patched or the malicious content is manually removed. This creates a sustained threat vector that can compromise user data, website integrity, and potentially lead to full system compromise if the WordPress installation contains additional vulnerabilities. The vulnerability affects not only individual users but also the broader website community that relies on the plugin's functionality.
Mitigation strategies for CVE-2026-0736 should prioritize immediate patching of the affected plugin to version 2.4.9 or later, which contains the necessary security fixes. Organizations should also implement additional defensive measures such as restricting user privileges to prevent unauthorized access to the plugin's administrative functions, implementing web application firewalls to detect and block suspicious script injections, and conducting regular security audits of WordPress installations. The vulnerability demonstrates the importance of proper input validation and output escaping techniques as outlined in CWE-79, which specifically addresses cross-site scripting flaws. Security teams should also consider implementing content security policies to limit the execution of unauthorized scripts and establish monitoring procedures to detect unauthorized modifications to post meta fields. Regular security updates and patch management processes should be enforced across all WordPress plugins and themes to prevent similar vulnerabilities from persisting in the environment.