CVE-2010-0177 in Firefox
Summary
by MITRE
Mozilla Firefox before 3.0.19, 3.5.x before 3.5.9, and 3.6.x before 3.6.2, and SeaMonkey before 2.0.4, frees the contents of the window.navigator.plugins array while a reference to an array element is still active, which allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via unspecified vectors, related to a "dangling pointer vulnerability."
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Analysis
by VulDB Data Team • 05/05/2026
This vulnerability represents a critical memory management flaw in Mozilla Firefox and SeaMonkey browsers that stems from improper handling of the window.navigator.plugins array during garbage collection processes. The issue manifests when the browser frees memory associated with plugin array elements while references to those elements remain active in the application's memory space. This creates a dangling pointer condition where freed memory locations are still accessible through existing references, enabling attackers to manipulate memory contents and potentially execute arbitrary code. The vulnerability affects multiple browser versions including Firefox 3.0.18 and earlier, 3.5.8 and earlier, 3.6.1 and earlier, and SeaMonkey 2.0.3 and earlier, making it a widespread concern across the Mozilla ecosystem.
The technical implementation of this vulnerability involves a race condition between memory deallocation and active references within the browser's plugin management system. When the browser's garbage collector attempts to free memory associated with the window.navigator.plugins array, it does not properly account for active references to individual plugin objects within that array. This memory management error creates a situation where freed memory locations can be reused, and if an attacker can control the contents of that memory or manipulate the execution flow through existing references, they can achieve code execution. The vulnerability is classified as a dangling pointer issue, which is categorized under CWE-416 in the Common Weakness Enumeration system, representing use of freed memory. The attack vectors are particularly insidious because they can be triggered through web pages that access plugin information, making exploitation possible through standard web browsing activities without requiring special privileges or user interaction beyond visiting malicious websites.
The operational impact of this vulnerability extends beyond simple application crashes to potentially enable full remote code execution capabilities. Attackers can leverage this flaw to inject malicious code into the browser process, potentially leading to complete system compromise. The denial of service aspect manifests as application crashes that can be triggered repeatedly, disrupting user sessions and potentially enabling DoS attacks against specific targets. From an adversary perspective, this vulnerability maps to several ATT&CK techniques including T1059 for command and script execution, T1070 for indicator removal, and T1210 for exploitation of remote services. The vulnerability is particularly dangerous in enterprise environments where users may visit untrusted websites or where browser-based attacks are common, as it can be exploited through standard web browsing without requiring additional attack vectors or user interaction.
Mitigation strategies for this vulnerability require immediate patching of affected browser versions to the latest stable releases that contain memory management fixes. Organizations should implement browser hardening measures including disabling unnecessary plugin functionality, restricting plugin access through content security policies, and maintaining up-to-date browser versions through automated patch management systems. Security teams should monitor for exploitation attempts through network traffic analysis and web application firewalls that can detect malicious plugin-related requests. The vulnerability highlights the importance of proper memory management practices in browser engines and serves as a reminder of the critical nature of secure coding practices, particularly in memory-intensive applications. Users should be educated about the risks of visiting untrusted websites and the importance of keeping browsers updated, while administrators should implement comprehensive security monitoring to detect potential exploitation attempts. Additionally, browser vendors should implement more robust memory management systems and conduct thorough security testing of plugin handling mechanisms to prevent similar vulnerabilities from emerging in future releases.