CVE-2004-2130 in phpBB
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in privmsg.php in phpBB 2.0.6 allow remote attackers to execute arbitrary script or HTML via the (1) folder or (2) mode variables.
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Analysis
by VulDB Data Team • 05/20/2025
The vulnerability described in CVE-2004-2130 represents a critical cross-site scripting flaw affecting phpBB version 2.0.6, specifically within the privmsg.php script. This issue falls under the CWE-79 category of Cross-Site Scripting, which is one of the most prevalent and dangerous web application security vulnerabilities. The vulnerability manifests when the application fails to properly sanitize user input parameters, allowing malicious actors to inject malicious scripts into web pages viewed by other users. In this particular case, the attack vectors target the folder and mode variables within the private messaging functionality of the bulletin board system.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP request parameters sent to the privmsg.php script. When attackers submit specially crafted folder or mode values containing malicious HTML or JavaScript code, the phpBB application processes these inputs without adequate validation or sanitization. The vulnerable code likely directly incorporates these parameters into the HTML output without proper encoding or filtering, creating an environment where injected scripts can execute in the context of other users' browsers. This occurs because the application does not distinguish between legitimate user content and potentially harmful script code, allowing the malicious payload to be rendered as part of the normal page content.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to perform various malicious activities through the compromised user sessions. Attackers can leverage this vulnerability to steal session cookies, redirect users to malicious websites, deface the bulletin board, or even execute more sophisticated attacks such as credential theft or privilege escalation within the forum environment. The vulnerability affects all users of the affected phpBB version, making it particularly dangerous as it can be exploited by anyone with access to the forum's private messaging functionality. From an ATT&CK perspective, this vulnerability maps to T1531 Access Token Manipulation and T1059 Command and Scripting Interpreter, as it enables attackers to execute arbitrary code within user contexts.
The remediation for this vulnerability requires immediate implementation of proper input validation and output encoding mechanisms. System administrators should upgrade to phpBB version 2.0.7 or later, which contains the necessary patches to address these XSS vulnerabilities. Additionally, implementing proper parameter sanitization techniques, including the use of HTML entity encoding for all user-supplied data before rendering in web pages, will prevent similar issues. Organizations should also consider implementing Content Security Policy headers and regular security auditing of web applications to identify and remediate similar vulnerabilities. The vulnerability demonstrates the critical importance of input validation in web applications and aligns with security best practices outlined in OWASP Top Ten and NIST Cybersecurity Framework guidelines.