CVE-2009-2665 in Firefox
Summary
by MITRE
The nsDocument::SetScriptGlobalObject function in content/base/src/nsDocument.cpp in Mozilla Firefox 3.5.x before 3.5.2, when certain add-ons are enabled, does not properly handle a Link HTTP header, which allows remote attackers to execute arbitrary JavaScript with chrome privileges via a crafted web page, related to an incorrect security wrapper.
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Analysis
by VulDB Data Team • 04/09/2025
The vulnerability identified as CVE-2009-2665 represents a critical security flaw in Mozilla Firefox versions 3.5.x prior to 3.5.2, specifically within the nsDocument::SetScriptGlobalObject function located in content/base/src/nsDocument.cpp. This vulnerability manifests when certain add-ons are enabled and exploits improper handling of the Link HTTP header, creating a pathway for remote code execution with elevated chrome privileges. The flaw stems from an incorrect security wrapper implementation that fails to properly validate or sanitize HTTP header content before processing it within the browser's document object model.
The technical exploitation of this vulnerability occurs through a carefully crafted web page that includes a malicious Link HTTP header, which when processed by the affected Firefox version triggers the flawed nsDocument::SetScriptGlobalObject function. This function is responsible for establishing the global script object within the document context, but due to inadequate security measures, it allows attacker-controlled JavaScript code to be executed with chrome privileges. The security wrapper mechanism that should prevent such privilege escalation is bypassed, enabling remote attackers to execute arbitrary JavaScript code that operates with the same privileges as the browser's chrome environment. This represents a severe cross-site scripting vulnerability that could be leveraged to perform actions such as reading or modifying sensitive data, executing commands on the underlying system, or even installing malware.
The operational impact of this vulnerability extends beyond typical web-based attacks, as the chrome privileges granted to the executed JavaScript code provide access to the browser's internal components and system resources. Attackers could potentially exploit this to access user data, manipulate browser settings, or perform actions that would normally be restricted to privileged browser processes. The vulnerability is particularly dangerous because it requires no user interaction beyond visiting a malicious webpage, making it a prime candidate for drive-by download attacks. The affected versions of Firefox were widely used, amplifying the potential impact of this vulnerability across numerous users and organizations.
Security mitigations for CVE-2009-2665 primarily involve updating to Firefox 3.5.2 or later versions where the vulnerability has been patched. Organizations should implement immediate patch management procedures to ensure all affected systems are updated. Additionally, network administrators can deploy web application firewalls or content filtering solutions that can detect and block malicious Link HTTP headers. The vulnerability aligns with CWE-200, which addresses improper output neutralization for logs, and relates to ATT&CK techniques involving privilege escalation and code execution. Browser vendors should also consider implementing stricter validation of HTTP headers and enhancing security wrapper mechanisms to prevent similar issues in future implementations. This vulnerability demonstrates the critical importance of proper security context handling and the potential consequences of inadequate privilege separation in browser security models.