CVE-2009-4736 in CommonSense CMS
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in search.php in CommonSense CMS 5.0 allows remote attackers to inject arbitrary web script or HTML via the q parameter.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 05/03/2026
The CVE-2009-4736 vulnerability represents a critical cross-site scripting flaw discovered in CommonSense CMS version 5.0, specifically within the search.php component. This vulnerability exposes the content management system to malicious injection attacks that can compromise user sessions and potentially lead to unauthorized access to sensitive data. The flaw manifests when the application fails to properly sanitize user input passed through the q parameter, creating an avenue for attackers to execute malicious scripts within the context of other users' browsers. The vulnerability falls under the category of CWE-79, which specifically addresses cross-site scripting weaknesses in web applications, making it a well-documented and severe security concern that affects the integrity of web-based systems.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious payload containing HTML or JavaScript code and submits it through the search functionality using the q parameter. When the vulnerable application processes this input without proper sanitization or output encoding, the malicious code gets embedded into the search results page and subsequently executed in the browsers of unsuspecting users who view the affected content. This type of attack leverages the trust relationship between the web application and its users, allowing threat actors to bypass normal security controls and potentially escalate their privileges or steal session cookies. The vulnerability demonstrates a classic failure in input validation and output encoding practices that are fundamental to preventing XSS attacks according to industry best practices.
The operational impact of CVE-2009-4736 extends beyond simple script execution, as it can enable sophisticated attack vectors including session hijacking, credential theft, and redirection to malicious websites. Attackers can leverage this vulnerability to steal user authentication tokens, monitor user activities, or even modify content within the CMS environment. The affected CommonSense CMS 5.0 platform becomes vulnerable to persistent XSS attacks where malicious scripts can remain active on the server and affect multiple users over time. This vulnerability directly relates to ATT&CK technique T1531 which focuses on establishing persistent access through web application vulnerabilities, and represents a significant risk to organizations relying on outdated CMS versions that have not received security updates.
Mitigation strategies for this vulnerability require immediate implementation of proper input sanitization and output encoding mechanisms throughout the application. Organizations should implement strict validation of all user-supplied input, particularly parameters like q in search functions, ensuring that any potentially dangerous characters or script tags are properly escaped or removed before processing. The recommended approach involves applying context-specific encoding when rendering user input back to the browser, such as HTML entity encoding for content displayed in web pages. Additionally, implementing a comprehensive content security policy can provide additional protection layers against XSS attacks by restricting the sources from which scripts can be loaded and executed. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other application components, while maintaining up-to-date CMS installations and applying security patches promptly to prevent exploitation of known vulnerabilities.