CVE-2018-0866 in Internet Explorer
Summary
by MITRE
Internet Explorer in Microsoft Windows 7 SP1, Windows Server 2008 and R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 and R2, Windows 10 Gold, 1511, 1607, 1703, 1709, and Windows Server 2016 allows remote code execution, due to how the scripting engine handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2018-0834, CVE-2018-0835, CVE-2018-0836, CVE-2018-0837, CVE-2018-0838, CVE-2018-0840, CVE-2018-0856, CVE-2018-0857, CVE-2018-0858, CVE-2018-0859, CVE-2018-0860, and CVE-2018-0861.
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Analysis
by VulDB Data Team • 09/13/2025
The vulnerability identified as CVE-2018-0866 represents a critical memory corruption issue within Microsoft Internet Explorer's scripting engine that affects multiple Windows operating systems including Windows 7 SP1 through Windows 10 versions 1511, 1607, 1703, and 1709 along with their respective server editions. This flaw specifically targets the way the scripting engine manages objects in memory, creating opportunities for attackers to execute arbitrary code remotely without user interaction. The vulnerability stems from improper handling of memory operations within the JavaScript engine, which is part of the Windows Scripting Host component that enables execution of script code within Internet Explorer.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where memory is accessed beyond its allocated boundaries. Attackers can exploit this memory corruption by crafting malicious web content that triggers the vulnerable scripting engine behavior when processing specific objects in memory. The flaw operates at the intersection of memory management and code execution, allowing adversaries to manipulate heap memory structures through carefully constructed script code that causes the browser to execute unintended instructions. This type of vulnerability falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter, specifically targeting the Windows Command Shell and PowerShell execution contexts.
The operational impact of CVE-2018-0866 is severe as it enables remote code execution with system-level privileges when users visit compromised websites or open maliciously crafted web pages. The vulnerability does not require user interaction beyond normal web browsing, making it particularly dangerous in targeted attacks where adversaries can deliver malicious payloads through phishing campaigns or compromised websites. Successful exploitation can result in complete system compromise, allowing attackers to install malware, steal sensitive data, or establish persistent backdoors within the affected systems. The widespread availability of Internet Explorer across multiple Windows versions means that a large attack surface exists for potential exploitation.
Mitigation strategies for CVE-2018-0866 should include immediate deployment of Microsoft security updates and patches released through Windows Update or Microsoft Update Catalog. Organizations should implement browser hardening measures such as disabling unnecessary scripting features, implementing strict content security policies, and using enhanced browser security configurations. Network-based protections like web application firewalls and intrusion detection systems can help detect and block exploitation attempts. Additionally, security awareness training for users to avoid visiting untrusted websites and opening suspicious email attachments remains crucial. The vulnerability demonstrates the importance of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect against zero-day exploits targeting widely used software components. Microsoft's security advisory recommends immediate patch deployment as the primary remediation measure, with additional network monitoring and endpoint protection solutions providing layered defense against potential exploitation attempts.