CVE-2013-2551 in Internet Explorer
Summary
by MITRE
Use-after-free vulnerability in Microsoft Internet Explorer 6 through 10 allows remote attackers to execute arbitrary code via a crafted web site that triggers access to a deleted object, as demonstrated by VUPEN during a Pwn2Own competition at CanSecWest 2013, aka "Internet Explorer Use After Free Vulnerability," a different vulnerability than CVE-2013-1308 and CVE-2013-1309.
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Analysis
by VulDB Data Team • 04/22/2026
The vulnerability identified as CVE-2013-2551 represents a critical use-after-free flaw in Microsoft Internet Explorer versions 6 through 10, demonstrating a fundamental memory management weakness that enables remote code execution. This vulnerability operates through a sophisticated attack vector where malicious web content triggers the execution of code on vulnerable systems, making it particularly dangerous in enterprise environments where users may inadvertently visit compromised websites. The flaw was prominently demonstrated during the Pwn2Own competition at CanSecWest 2013 by VUPEN security researchers, showcasing how attackers could leverage this weakness to gain complete system control without requiring user interaction beyond visiting a malicious webpage.
The technical nature of this vulnerability stems from improper memory management within Internet Explorer's object handling mechanisms, specifically when processing certain web page elements that result in objects being freed from memory while still being referenced by active code paths. When Internet Explorer encounters a crafted web page containing malicious JavaScript or ActiveX components, it may attempt to access memory locations that have already been deallocated, creating a use-after-free condition that attackers can exploit to execute arbitrary code with the privileges of the current user. This type of vulnerability falls under CWE-416, which specifically addresses the use of freed memory conditions in software applications. The vulnerability is particularly insidious because it can be triggered automatically through web browsing activities, requiring no special user actions beyond visiting a compromised site.
The operational impact of CVE-2013-2551 extends far beyond simple exploitation, as it represents a complete compromise of system security that can lead to data theft, system control, and further lateral movement within networks. Attackers can leverage this vulnerability to install backdoors, steal sensitive information, or establish persistent access to compromised systems, making it a prime target for advanced persistent threat actors. The vulnerability affects a wide range of Internet Explorer versions, creating a significant attack surface across both legacy and newer systems that may not have been properly updated. Organizations running these vulnerable versions face substantial risk, as the attack can be delivered through various vectors including phishing emails, malicious advertisements, or compromised websites, all of which can be difficult to detect and prevent through traditional security measures.
Mitigation strategies for this vulnerability require immediate patching of affected Internet Explorer versions, as Microsoft released security updates to address the specific memory management flaws. Organizations should implement comprehensive patch management processes to ensure all systems are updated promptly, while also deploying additional security layers such as web application firewalls and browser isolation techniques. The vulnerability's classification under the ATT&CK framework as part of the exploitation phase highlights the need for defensive measures including network monitoring, behavioral analysis, and user education to detect and prevent exploitation attempts. Given that this vulnerability was demonstrated at a major security conference, organizations should also consider implementing network segmentation, restricting Internet Explorer usage where possible, and maintaining up-to-date threat intelligence to identify potential exploitation attempts targeting this specific flaw.