CVE-2009-3856 in Twiglight
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the default URI in news/ in Twilight CMS before 4.1 allows remote attackers to inject arbitrary web script or HTML via the calendar parameter. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 08/26/2025
The CVE-2009-3856 vulnerability represents a critical cross-site scripting flaw in Twilight CMS versions prior to 4.1, specifically affecting the default URI handling within the news/ module. This vulnerability resides in the calendar parameter processing mechanism, creating an exploitable entry point for malicious actors to execute arbitrary web scripts or HTML code within the context of affected user sessions. The flaw demonstrates a classic input validation failure where user-supplied data enters the application without proper sanitization or encoding, allowing attackers to inject malicious payloads that persist in the application's response.
The technical implementation of this vulnerability stems from inadequate parameter validation within the calendar parameter of the news/ module's default URI handler. When Twilight CMS processes requests containing malicious input in the calendar parameter, it fails to properly escape or validate the input before incorporating it into dynamic web content. This oversight creates a persistent XSS vector that can be exploited by remote attackers who craft malicious URLs containing script payloads. The vulnerability falls under CWE-79 - Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to sanitize user input before it is rendered in web pages.
From an operational impact perspective, this vulnerability enables attackers to perform session hijacking, defacement of content, data theft, and redirection to malicious sites. An attacker could inject malicious scripts that steal cookies, redirect users to phishing sites, or execute commands on behalf of authenticated users. The attack surface is particularly concerning as it affects the default URI handling mechanism, meaning any user accessing the news/ module through the default interface could be vulnerable to exploitation. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1059.001 - Command and Scripting Interpreter: PowerShell and T1566.001 - Phishing: Spearphishing Attachment, where attackers leverage XSS to establish persistent access or deliver additional malicious payloads.
The remediation strategy for CVE-2009-3856 requires immediate implementation of input validation and output encoding measures within the Twilight CMS application. Organizations should ensure that all user-supplied parameters, particularly those used in dynamic content generation, undergo proper sanitization before being incorporated into web responses. The fix should implement proper HTML entity encoding for all output, utilize Content Security Policy headers, and apply input validation that rejects or removes potentially malicious characters. Additionally, the upgrade to Twilight CMS version 4.1 or later is essential as this release includes the necessary patches to address the input validation deficiencies. Security teams should also implement web application firewall rules to detect and block suspicious patterns in calendar parameter values, and conduct thorough security testing to ensure no similar vulnerabilities exist in other URI handlers within the application.