CVE-2010-0171 in Firefox
Summary
by MITRE
Mozilla Firefox 3.0.x before 3.0.18, 3.5.x before 3.5.8, and 3.6.x before 3.6.2; Thunderbird before 3.0.2; and SeaMonkey before 2.0.3 allow remote attackers to perform cross-origin keystroke capture, and possibly conduct cross-site scripting (XSS) attacks, by using the addEventListener and setTimeout functions in conjunction with a wrapped object. NOTE: this vulnerability exists because of an incomplete fix for CVE-2007-3736.
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Analysis
by VulDB Data Team • 05/03/2026
This vulnerability represents a sophisticated cross-origin security flaw that affects multiple Mozilla products including Firefox, Thunderbird, and SeaMonkey. The issue stems from an incomplete remediation of CVE-2007-3736, creating a persistent security gap that allows remote attackers to exploit cross-origin keystroke capture capabilities. The vulnerability specifically leverages the interaction between addEventListener and setTimeout JavaScript functions when combined with wrapped objects, enabling attackers to capture keystrokes from different origins and potentially execute cross-site scripting attacks.
The technical implementation of this vulnerability exploits the JavaScript event handling mechanisms within the browser's security model. When attackers utilize addEventListener in conjunction with setTimeout functions, they can manipulate the timing and execution context of JavaScript events to access wrapped objects that should normally be restricted by cross-origin policies. This creates a scenario where keystroke data from one origin can be intercepted and potentially exfiltrated to an attacker-controlled domain, effectively bypassing the same-origin policy that normally protects users from cross-origin data theft.
The operational impact of this vulnerability extends beyond simple keystroke capture to potentially enable full cross-site scripting attacks within the affected browser environments. Attackers can leverage this capability to inject malicious scripts into web pages, steal session cookies, perform unauthorized actions on behalf of users, and potentially escalate privileges within the browser context. The vulnerability affects multiple versions across different Mozilla products, making it particularly dangerous as it impacts a wide user base with varying security configurations and update schedules.
Security researchers categorize this vulnerability under CWE-200, which addresses "Information Exposure," and it aligns with ATT&CK techniques related to credential access and privilege escalation through browser-based attacks. The incomplete fix for CVE-2007-3736 demonstrates the complexity of addressing browser security issues and highlights the importance of comprehensive vulnerability remediation. Organizations should prioritize immediate patching of affected versions to prevent exploitation, as the vulnerability creates a persistent threat vector that can be easily weaponized by threat actors. The remediation process requires updating to the specified patched versions of Firefox, Thunderbird, and SeaMonkey, ensuring that all users within the organization have upgraded to prevent potential compromise through this cross-origin keystroke capture mechanism.