CVE-2026-83741
Summary
by MITRE • 10/13/2026
Use after free in Internet Explorer allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 10/13/2026
The vulnerability described constitutes a critical use-after-free flaw within Microsoft Internet Explorer, a legacy web browser that has historically been a frequent target for exploitation due to its complex architecture and deep integration with the Windows operating system. This specific class of memory corruption error occurs when the application continues to reference a block of memory after it has already been freed or deallocated by the system. In the context of Internet Explorer, this typically involves JavaScript engines or ActiveX controls that manage dynamic object lifecycles. When an attacker crafts a malicious web page containing specially designed script code, they can trigger conditions where objects are destroyed prematurely while references to those objects remain active in memory. This discrepancy allows the attacker to manipulate how the browser interprets the freed memory region, effectively gaining control over program flow and data structures that were intended to be inaccessible or read-only.
From a technical perspective, this vulnerability falls under the Common Weakness Enumeration category CWE-416, which defines use-after-free errors as accessing memory after it has been released. The operational impact of such a flaw is severe because it enables arbitrary code execution with the privileges of the current user process. Since Internet Explorer often runs with elevated permissions or interacts directly with system-level components through COM objects and ActiveX controls, successfully exploiting this vulnerability allows an attacker to bypass standard security boundaries. This leads to local privilege escalation, where an unprivileged user can execute commands as a higher-privilege account, potentially gaining administrative control over the affected machine. The attack vector is classified under remote code execution principles within the MITRE ATT&CK framework, specifically leveraging techniques related to client-side exploitation and browser-based attacks such as T1203 or T1189 depending on the specific delivery mechanism used to host the malicious content.
Mitigation strategies for this vulnerability primarily involve applying the relevant security patches released by Microsoft that address the memory management logic within Internet Explorer's rendering engine and script interpreter organizations must ensure that all systems running vulnerable versions of Internet Explorer are updated with the latest cumulative updates. Additionally, since Internet Explorer is deprecated and no longer receives active development or support in modern Windows environments, the most effective long-term mitigation is to disable the browser entirely using group policy settings and migrate users to a supported web browser such as Microsoft Edge which employs more robust memory safety features like heap isolation and structured exception handling. For organizations that must maintain legacy compatibility, implementing application whitelisting policies can prevent unauthorized scripts from executing within the browser context, thereby reducing the attack surface available to potential exploiters attempting to leverage this use-after-free condition for privilege escalation purposes.