CVE-2012-4969 in Internet Explorer
Summary
by MITRE
Use-after-free vulnerability in the CMshtmlEd::Exec function in mshtml.dll in Microsoft Internet Explorer 6 through 9 allows remote attackers to execute arbitrary code via a crafted web site, as exploited in the wild in September 2012.
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Analysis
by VulDB Data Team • 04/22/2026
The CVE-2012-4969 vulnerability represents a critical use-after-free flaw in Microsoft Internet Explorer's mshtml.dll component that affected versions 6 through 9. This vulnerability resides within the CMshtmlEd::Exec function, which handles various HTML editing operations within the browser's rendering engine. The flaw manifests when the browser processes maliciously crafted web content that triggers improper memory management during HTML editing operations, creating conditions where freed memory locations can be accessed and reused by malicious code.
The technical exploitation of this vulnerability leverages the fundamental memory management error where a pointer continues to reference memory that has already been freed and potentially reallocated. When Internet Explorer processes certain HTML elements through the CMshtmlEd::Exec function, it fails to properly validate or manage the lifecycle of memory objects, allowing attackers to manipulate the freed memory space. This creates a scenario where attacker-controlled data can be written to memory locations that were previously occupied by legitimate browser objects, ultimately enabling arbitrary code execution. The vulnerability is particularly dangerous because it operates within the browser's core HTML processing pipeline, making it difficult to detect and prevent through standard security measures.
From an operational perspective, this vulnerability was actively exploited in the wild during September 2012, demonstrating its real-world impact and the sophistication of attackers who weaponized it. The exploit typically involves crafting web pages with specific HTML structures and JavaScript elements that trigger the vulnerable code path in mshtml.dll. Once successfully exploited, attackers gain full control over the affected system, potentially leading to complete system compromise, data theft, or further lateral movement within networks. The widespread impact stems from the fact that Internet Explorer 6 through 9 were still prevalent in enterprise environments, making organizations particularly vulnerable to this attack vector.
Security professionals should recognize this vulnerability as mapping to CWE-416, which specifically addresses use-after-free conditions in memory management. The exploit techniques align with ATT&CK tactics involving exploitation of known vulnerabilities and privilege escalation, as attackers can leverage this flaw to execute code with the privileges of the targeted user. Organizations should implement immediate mitigations including applying the relevant Microsoft security patches, enabling enhanced security features like Data Execution Prevention, and deploying web application firewalls to detect and block malicious content. Additionally, browser isolation techniques and security awareness training can help reduce the attack surface, while regular vulnerability assessments should focus on identifying outdated Internet Explorer installations that may still be exposed to this and similar legacy vulnerabilities.