CVE-2006-6142 in SquirrelMail
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in SquirrelMail 1.4.0 through 1.4.9 allow remote attackers to inject arbitrary web script or HTML via the (1) mailto parameter in (a) webmail.php, the (2) session and (3) delete_draft parameters in (b) compose.php, and (4) unspecified vectors involving "a shortcoming in the magicHTML filter."
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/15/2025
The vulnerability CVE-2006-6142 represents a critical cross-site scripting flaw affecting SquirrelMail versions 1.4.0 through 1.4.9, demonstrating a fundamental weakness in web application input validation and output sanitization mechanisms. This vulnerability classifies under CWE-79 as improper neutralization of input during web output, where user-supplied data is not adequately filtered before being rendered in web pages. The flaw manifests across multiple entry points within the SquirrelMail webmail interface, creating multiple attack vectors that collectively increase the exploitability and potential impact of the vulnerability.
The technical implementation of this vulnerability occurs through several distinct parameter injection points within the application's core files. The primary attack vectors include the mailto parameter in webmail.php, which allows malicious payloads to be injected when processing email addresses, and the session and delete_draft parameters in compose.php, where crafted input can be executed during message composition operations. Additionally, the vulnerability encompasses unspecified vectors related to a shortcoming in the magicHTML filter, indicating that the application's HTML sanitization mechanism fails to properly handle certain input patterns, potentially allowing attackers to bypass existing security controls. These multiple attack surfaces create a comprehensive exploitation framework that can be leveraged to execute malicious scripts in the context of a victim's browser session.
The operational impact of CVE-2006-6142 extends beyond simple script execution, as it enables attackers to perform session hijacking, steal user credentials, and conduct phishing attacks against authenticated users. When exploited, these XSS vulnerabilities can allow attackers to manipulate the webmail interface, redirect users to malicious sites, or execute arbitrary code that compromises the confidentiality and integrity of user communications. The vulnerability particularly affects email users who may be tricked into clicking malicious links, as the attack can be delivered through email messages containing crafted URLs that exploit the vulnerable parameters. This creates a significant risk for organizations relying on SquirrelMail for email services, as successful exploitation can lead to unauthorized access to sensitive email communications and potential lateral movement within network environments.
Organizations affected by this vulnerability should prioritize immediate remediation through version upgrading to SquirrelMail 1.5.0 or later, which contains the necessary patches to address the XSS flaws. Additionally, implementing proper input validation and output encoding measures can provide defense-in-depth protection against similar vulnerabilities. The remediation approach should include comprehensive testing of all user-supplied inputs and ensuring that all web application output is properly escaped before rendering. Security controls such as content security policies and web application firewalls can also provide additional protection against exploitation attempts. This vulnerability aligns with ATT&CK technique T1566.001 for initial access through spearphishing attachments and T1071.001 for application layer protocol usage, demonstrating how client-side vulnerabilities can enable broader attack chains within enterprise environments.