CVE-2012-5567 in Groupware
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Horde Kronolith Calendar Application H4 before 3.0.18, as used in Horde Groupware Webmail Edition before 4.0.9, allow remote attackers to inject arbitrary web script or HTML via crafted event location parameters in the (1) month, (2) monthlist, or (3) prevmonthlist fields, related to portal blocks.
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Analysis
by VulDB Data Team • 05/09/2026
The vulnerability CVE-2012-5567 represents a critical cross-site scripting weakness affecting the Horde Kronolith Calendar Application version H4 and the broader Horde Groupware Webmail Edition prior to version 4.0.9. This flaw resides in the calendar application's handling of event location parameters within specific portal block functionalities, creating a significant security risk for web applications utilizing these components. The vulnerability specifically targets three distinct field parameters including month, monthlist, and prevmonthlist which are commonly used in calendar portal displays and user interfaces.
The technical exploitation of this vulnerability occurs when remote attackers manipulate event location data within calendar applications that utilize the affected Horde components. The flaw stems from inadequate input validation and output encoding mechanisms within the calendar application's portal block rendering functions. When users view calendar portal blocks containing crafted event location parameters, the malicious script code becomes executed within the context of the victim's browser session, bypassing standard security measures that protect against unauthorized script execution. This vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws in web applications, where the application fails to properly validate or encode user-supplied data before incorporating it into dynamically generated web content.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with the ability to execute arbitrary web scripts or HTML code within user sessions. This capability enables malicious actors to perform various harmful actions including session hijacking, data theft, redirection to malicious sites, and potential privilege escalation within the application environment. The vulnerability affects users of Horde Groupware Webmail Edition, which was widely deployed in enterprise and organizational environments, amplifying the potential scope of exploitation. Attackers could leverage this vulnerability to compromise user sessions, steal authentication tokens, or redirect users to phishing sites that appear legitimate within the trusted application context.
Security professionals should implement immediate mitigation strategies including upgrading to the patched versions of Horde Kronolith Calendar Application version 3.0.18 and Horde Groupware Webmail Edition version 4.0.9. The remediation process involves ensuring that all event location parameters undergo proper input validation and output encoding before being rendered in portal blocks. Organizations should also consider implementing web application firewalls that can detect and block suspicious parameter patterns, as well as establishing comprehensive monitoring for unusual script injection attempts. The vulnerability demonstrates the importance of maintaining up-to-date security patches and implementing robust input validation mechanisms as outlined in the ATT&CK framework's defense-in-depth strategies, particularly focusing on the prevention of code injection attacks through proper data sanitization and validation controls.