CVE-2018-0891 in Internet Explorer
Summary
by MITRE
ChakraCore, and 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, and Internet Explorer and Microsoft Edge in Windows 10 Gold, 1511, 1607, 1703, 1709, and Windows Server 2016 allow information disclosure, due to how the scripting engine handles objects in memory, aka "Scripting Engine Information Disclosure Vulnerability". This CVE ID is unique from CVE-2018-0939.
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Analysis
by VulDB Data Team • 09/04/2025
The vulnerability identified as CVE-2018-0891 represents a critical information disclosure flaw within Microsoft's ChakraCore JavaScript engine and Internet Explorer implementations across multiple Windows operating systems. This vulnerability specifically affects Windows 7 SP1, Windows Server 2008 and R2 SP1, Windows 8.1, Windows RT 8.1, Windows Server 2012 and R2, and various Windows 10 versions including Gold, 1511, 1607, 1703, and 1709, along with Windows Server 2016. The flaw stems from improper handling of objects in memory by the scripting engine, creating potential avenues for attackers to extract sensitive information from system memory.
The technical root cause of this vulnerability lies in how the ChakraCore engine manages object references and memory allocation during JavaScript execution. When processing certain JavaScript objects, the engine fails to properly validate or sanitize memory access patterns, leading to information disclosure scenarios where attackers can potentially read data from adjacent memory locations. This type of vulnerability falls under the CWE-200 category of "Information Exposure" and specifically relates to improper handling of memory objects within scripting environments. The flaw enables attackers to potentially access sensitive data that should remain private, including credentials, application data, or system information that could be used for further exploitation.
The operational impact of CVE-2018-0891 extends beyond simple information disclosure, as it provides attackers with valuable reconnaissance data that can be leveraged for more sophisticated attacks. In the context of the ATT&CK framework, this vulnerability maps to the Information Gathering tactic where adversaries collect system information to plan subsequent operations. The vulnerability can be exploited through malicious web pages delivered via phishing campaigns or compromised websites, where users' browsers execute malicious JavaScript code that triggers the memory access flaw. Attackers can potentially extract sensitive information such as memory addresses, application data, or even partial credentials from the affected systems, making this vulnerability particularly dangerous in targeted attack scenarios.
Mitigation strategies for CVE-2018-0891 should prioritize immediate patch deployment through Microsoft's regular security updates, as the vulnerability has been addressed through security patches released in the corresponding monthly update cycles. Organizations should implement browser hardening measures including disabling unnecessary JavaScript features, employing content security policies, and utilizing sandboxing technologies to limit potential damage from exploitation attempts. Network monitoring should be enhanced to detect anomalous JavaScript behavior patterns that might indicate exploitation attempts. Additionally, security teams should conduct regular vulnerability assessments to ensure all affected systems receive proper updates and that legacy systems are properly secured or migrated to supported platforms to prevent exploitation of this and similar vulnerabilities.