CVE-2005-2539 in FlatNuke
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in FlatNuke 2.5.5 and possibly earlier versions allow remote attackers to inject arbitrary web script or HTML via the (1) bodycolor, (2) backimage, (3) theme, or (4) logo parameter to structure.php, (5) admin, (6) admin_mail, or (7) back parameter to footer.php, or (8) the message body in a news post.
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Analysis
by VulDB Data Team • 07/05/2025
The vulnerability identified as CVE-2005-2539 represents a critical cross-site scripting flaw affecting FlatNuke 2.5.5 and potentially earlier versions of this content management system. This vulnerability stems from inadequate input validation and output encoding mechanisms within the application's handling of user-supplied data. The flaw manifests across multiple entry points within the application's core files, specifically targeting parameters within structure.php and footer.php, as well as the message body field in news post submissions. The vulnerability classification aligns with CWE-79 which defines cross-site scripting as a weakness where untrusted data is sent to a web browser without proper validation or encoding, allowing attackers to inject malicious scripts.
The technical exploitation of this vulnerability occurs through the injection of malicious HTML or JavaScript code into the application's output streams. Attackers can manipulate the bodycolor, backimage, theme, or logo parameters in structure.php to inject script tags that execute in the context of other users' browsers. Similarly, the admin, admin_mail, back parameters in footer.php provide additional attack vectors where malicious code can be injected. The most concerning aspect involves the message body field in news posts, which allows attackers to embed malicious scripts that persist in the application's content. This persistent nature makes the vulnerability particularly dangerous as it can affect multiple users over extended periods. The vulnerability operates under the principle of reflected and stored XSS patterns, where the malicious code is either reflected back to users or stored within the application's database.
The operational impact of this vulnerability extends beyond simple data theft or defacement. Successful exploitation enables attackers to hijack user sessions, redirect users to malicious websites, steal sensitive cookies, or perform unauthorized actions on behalf of victims. The vulnerability affects the core functionality of FlatNuke's user interface and content management capabilities, potentially compromising the entire application's integrity. Users with administrative privileges face heightened risk as attackers could gain elevated access to modify or delete content, alter user permissions, or manipulate the application's configuration. The vulnerability's persistence across multiple parameters indicates a systemic flaw in the application's input sanitization processes, suggesting that attackers have multiple pathways to achieve their objectives. This widespread exposure increases the likelihood of successful exploitation and makes the vulnerability particularly attractive to automated attack tools.
Mitigation strategies for CVE-2005-2539 should focus on implementing comprehensive input validation and output encoding mechanisms throughout the application. The most effective immediate solution involves sanitizing all user-supplied input before processing or storing it within the application, particularly for parameters related to color, image, theme, and message body fields. Implementing proper HTML encoding for all dynamic content output helps prevent script execution in browser contexts. The application should enforce strict validation rules that reject or sanitize any input containing potentially dangerous characters or script tags. Security headers such as Content Security Policy should be implemented to further restrict script execution and prevent unauthorized code injection. Additionally, developers should conduct regular security audits and input validation reviews to identify similar vulnerabilities across the codebase. Organizations should consider upgrading to supported versions of FlatNuke or migrating to more secure content management platforms. The vulnerability's classification under ATT&CK technique T1566 highlights the importance of network security monitoring to detect and prevent exploitation attempts. Regular security training for administrators and developers regarding secure coding practices remains essential to prevent similar vulnerabilities in future development cycles.