CVE-2005-3919 in PBLang
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in PBLang 4.65 allows remote attackers to inject arbitrary web script or HTML via multiple fields in (1) UCP.php and (2) SendPm.php.
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Analysis
by VulDB Data Team • 09/14/2025
The CVE-2005-3919 vulnerability represents a critical cross-site scripting flaw discovered in PBLang version 4.65, a web-based discussion forum software that was widely used in 2005. This vulnerability resides in the user control panel and private messaging components of the application, specifically affecting two key files: UCP.php and SendPm.php. The flaw stems from inadequate input validation and output encoding mechanisms within these modules, allowing malicious actors to inject arbitrary web scripts or HTML content directly into the application's response streams. The vulnerability affects multiple user input fields, making it particularly dangerous as attackers can exploit various entry points to compromise user sessions and execute malicious code within the context of other users' browsers.
The technical implementation of this XSS vulnerability follows the classic pattern where user-supplied data flows directly into HTML output without proper sanitization or encoding. When users interact with the UCP.php and SendPm.php scripts, their input is processed and displayed without adequate protection against script injection attacks. This allows attackers to craft malicious payloads that can execute in the victim's browser context, potentially leading to session hijacking, credential theft, or redirection to malicious websites. The vulnerability is classified as a reflected XSS attack since the malicious script is embedded in the request and immediately reflected back to the user's browser without being stored on the server. This flaw directly maps to CWE-79, which defines the weakness of insufficient input validation and output encoding in web applications, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter.
The operational impact of CVE-2005-3919 extends beyond simple data theft, as it provides attackers with the capability to manipulate user sessions and potentially gain unauthorized access to sensitive forum data. Attackers can exploit this vulnerability to steal session cookies, redirect users to phishing sites, or even modify forum content through malicious script execution. The widespread use of PBLang in 2005 meant that numerous websites were potentially exposed to this vulnerability, creating a significant attack surface for malicious actors. The vulnerability's persistence across multiple input fields in core user modules increases the attack surface considerably, as different user interactions can all serve as potential entry points for exploitation. Organizations using this forum software faced the risk of complete session compromise and potential data breaches, particularly when users accessed the forum from shared or public computing environments where session hijacking attacks could be easily executed.
Mitigation strategies for this vulnerability require immediate implementation of proper input validation and output encoding mechanisms throughout the affected application modules. The most effective remediation involves sanitizing all user input before processing and ensuring that all dynamic content is properly escaped when rendered in HTML contexts. Security patches should implement proper HTML entity encoding for all user-supplied data, particularly in the UCP.php and SendPm.php files, to prevent script execution in browser contexts. Organizations should also implement Content Security Policy headers to add an additional layer of protection against XSS attacks, though this should not replace proper input validation. Regular security audits and code reviews should be conducted to identify similar vulnerabilities in other application components, as this flaw demonstrates the importance of consistent security practices throughout web application development. The vulnerability serves as a critical reminder of the importance of implementing secure coding practices and the necessity of regular security assessments to identify and remediate XSS vulnerabilities before they can be exploited by malicious actors.