CVE-2004-2076 in vBulletin
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in search.php for Jelsoft vBulletin 3.0.0 RC4 allows remote attackers to inject arbitrary web script or HTML via the query parameter.
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Analysis
by VulDB Data Team • 06/17/2025
The vulnerability identified as CVE-2004-2076 represents a critical cross-site scripting flaw within the Jelsoft vBulletin 3.0.0 RC4 forum software, specifically affecting the search.php script. This issue arises from inadequate input validation and sanitization mechanisms that fail to properly filter user-supplied data before incorporating it into web responses. The vulnerability exists because the application directly reflects user input from the query parameter without implementing proper output encoding or validation controls, creating an avenue for malicious actors to execute arbitrary scripts within the context of other users' browsers.
The technical implementation of this vulnerability stems from the application's failure to sanitize the query parameter in search.php, which is commonly used to process search terms entered by forum users. When a user submits a search query, the application accepts the input and displays it back to the user in the search results page without proper HTML escaping or script validation. This allows an attacker to embed malicious JavaScript code or HTML content within the search query parameter, which then executes when other users view the search results page. The flaw specifically relates to CWE-79, which defines Cross-Site Scripting vulnerabilities as weaknesses that occur when an application includes untrusted data in new web pages without proper validation or encoding, or when it creates a new web page using that data without sufficient escaping.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, defacement of forum content, and redirection to malicious websites. An attacker could craft a search query containing malicious JavaScript that steals cookies from unsuspecting users, potentially compromising their authentication sessions and allowing unauthorized access to their accounts. The vulnerability also enables more sophisticated attacks such as phishing attempts where users might be redirected to fraudulent websites designed to capture login credentials or personal information. Additionally, the attacker could leverage this vulnerability to inject malicious code that modifies forum content, spreads malware, or disrupts normal forum operations through persistent script injection.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and output encoding mechanisms. Organizations should immediately implement proper HTML escaping for all user-supplied input before rendering it in web pages, ensuring that special characters such as angle brackets, quotes, and script tags are properly encoded. The implementation of Content Security Policy headers can provide additional protection by restricting the sources from which scripts can be loaded and executed within the forum environment. Regular security audits and code reviews should be conducted to identify similar input validation weaknesses in other parts of the application. According to ATT&CK framework, this vulnerability maps to T1059.007 for scripting and T1566.001 for credential access, highlighting the potential for both code execution and unauthorized access. Organizations should also consider implementing web application firewalls to detect and block malicious payloads attempting to exploit this vulnerability, while maintaining up-to-date security patches for the vBulletin platform to prevent exploitation of known vulnerabilities.