CVE-2009-4678 in Winn Guestbook
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in index.php in Winn Guestbook 2.4 allows remote attackers to inject arbitrary web script or HTML via the PATH_INFO.
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Analysis
by VulDB Data Team • 05/02/2026
The CVE-2009-4678 vulnerability represents a critical cross-site scripting flaw within the Winn Guestbook 2.4 web application that exposes users to potential malicious code execution. This vulnerability specifically targets the index.php file and leverages the PATH_INFO server variable to deliver malicious payloads. The flaw exists due to insufficient input validation and output sanitization mechanisms within the application's handling of URL path information, creating an exploitable entry point for remote attackers. The vulnerability classification aligns with CWE-79 which defines cross-site scripting as a weakness where untrusted data is embedded into web pages viewed by other users without proper validation or encoding.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL containing script code within the PATH_INFO component and directs a victim to access this specially crafted link. The application fails to properly sanitize or encode the PATH_INFO data before incorporating it into the web page output, allowing the malicious script to execute within the victim's browser context. This type of vulnerability enables attackers to perform various malicious activities including session hijacking, credential theft, defacement of the guestbook interface, and redirection to malicious websites. The vulnerability operates at the application layer and requires no special privileges to exploit, making it particularly dangerous as it can be triggered through simple web browsing activities.
The operational impact of CVE-2009-4678 extends beyond simple data theft or defacement, as it can serve as a launching point for more sophisticated attacks within the victim's browser environment. Attackers can leverage this vulnerability to execute persistent scripts that monitor user interactions, capture keystrokes, or manipulate the guestbook's functionality to inject additional malicious content. The vulnerability affects the integrity and confidentiality of the web application's user data, potentially compromising the privacy of visitors who submit entries to the guestbook. Additionally, the vulnerability can be exploited to establish a foothold for further attacks within the network, particularly if the guestbook is hosted on a server that provides access to other sensitive resources. This aligns with ATT&CK technique T1566 which covers social engineering methods including spearphishing with a link that can be used to deliver malicious payloads.
Mitigation strategies for CVE-2009-4678 should focus on implementing proper input validation and output encoding mechanisms throughout the application. The most effective approach involves sanitizing all user-supplied input including PATH_INFO data before incorporating it into web page output, utilizing proper HTML encoding techniques to prevent script execution. Organizations should also implement Content Security Policy headers to restrict the execution of unauthorized scripts within the application context. Regular security updates and patches should be applied to ensure the guestbook application remains protected against known vulnerabilities, with the specific fix involving proper sanitization of the PATH_INFO parameter in the index.php file. The vulnerability demonstrates the importance of defense-in-depth principles and proper secure coding practices, particularly the need to validate and sanitize all inputs regardless of their source, which directly relates to CWE-116 and the broader secure coding guidelines established by OWASP.