CVE-2007-1111 in ActiveCalendar
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in ActiveCalendar 1.2.0 allow remote attackers to inject arbitrary web script or HTML via the css parameter to (1) flatevents.php, (2) js.php, (3) mysqlevents.php, (4) m_2.php, (5) m_3.php, (6) m_4.php, (7) xmlevents.php, (8) y_2.php, or (9) y_3.php in data/.
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Analysis
by VulDB Data Team • 05/23/2025
The vulnerability identified as CVE-2007-1111 represents a critical cross-site scripting flaw affecting ActiveCalendar version 1.2.0, specifically targeting multiple script files within the data/ directory. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, where improperly validated user input is directly incorporated into web output without adequate sanitization or encoding. The affected files include flatevents.php, js.php, mysqlevents.php, and several other calendar-related scripts that process user-provided parameters. The vulnerability occurs when the css parameter is passed to any of these nine specific files, allowing malicious actors to inject arbitrary web scripts or HTML content that executes in the context of other users' browsers.
The technical exploitation of this vulnerability demonstrates a fundamental failure in input validation and output encoding practices within the ActiveCalendar application. When users interact with the calendar system and provide malicious input through the css parameter, the application fails to properly sanitize this input before incorporating it into dynamic web responses. This creates an environment where attackers can craft payloads that execute in the victim's browser context, potentially leading to session hijacking, credential theft, or other malicious activities. The vulnerability affects the entire range of calendar display functions since these scripts are responsible for rendering calendar events and user interfaces that incorporate user-supplied CSS styling parameters.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with persistent access to user sessions and potentially sensitive calendar data. An attacker could craft malicious CSS parameters that redirect users to phishing sites, steal session cookies, or inject malicious JavaScript that modifies calendar entries. The vulnerability affects all users who interact with the calendar system, making it particularly dangerous in environments where calendar data contains sensitive information or where users have administrative privileges. The wide range of affected files suggests a systemic code flaw in how the application handles user input, indicating that the sanitization process was not properly implemented across the entire calendar module.
Security practitioners should implement immediate mitigations including input validation and output encoding for all user-supplied parameters, particularly those related to CSS styling in web applications. The vulnerability aligns with ATT&CK technique T1566.001 for credential access through phishing and T1203 for exploitation of web applications. Organizations should ensure that all user-provided input is properly validated against a whitelist of acceptable characters and that output is encoded appropriately for the context in which it will be displayed. The recommended remediation involves implementing proper parameter validation and output encoding mechanisms, with a focus on ensuring that CSS parameters are sanitized before being processed by any calendar display functions. Additionally, regular security audits should verify that similar input validation issues do not exist in other components of the application, as this vulnerability demonstrates a pattern of insufficient sanitization that could affect other user input fields throughout the system.