CVE-2016-0189 in Windows
Summary
by MITRE
The Microsoft (1) JScript 5.8 and (2) VBScript 5.7 and 5.8 engines, as used in Internet Explorer 9 through 11 and other products, allow remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site, aka "Scripting Engine Memory Corruption Vulnerability," a different vulnerability than CVE-2016-0187.
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Analysis
by VulDB Data Team • 04/23/2026
The CVE-2016-0189 vulnerability represents a critical memory corruption flaw affecting Microsoft's scripting engines within Internet Explorer versions 9 through 11. This vulnerability specifically impacts the JScript 5.8 and VBScript 5.7 and 5.8 engines that are integral components of the browser's scripting infrastructure. The flaw enables remote attackers to execute arbitrary code or induce denial of service conditions through maliciously crafted web content, making it a significant threat to user security and system integrity. The vulnerability operates at a fundamental level within the browser's scripting engine architecture, where improper memory handling creates exploitable conditions that can be leveraged by attackers to gain unauthorized system access.
This memory corruption vulnerability stems from inadequate bounds checking and memory management within the scripting engines' interpretation and execution processes. When Internet Explorer processes malicious script code, the affected scripting engines fail to properly validate memory operations, leading to buffer overflows or use-after-free conditions that can be manipulated by attackers. The vulnerability specifically affects how the engines handle certain script constructs and memory allocation patterns, creating opportunities for attackers to inject malicious code into the browser's memory space. The flaw is particularly dangerous because it operates within the browser's core scripting capabilities, which are frequently used by legitimate web applications, making exploitation more likely and harder to detect.
The operational impact of CVE-2016-0189 extends beyond simple code execution to encompass potential system compromise and persistent security breaches. Attackers can leverage this vulnerability to escalate privileges, install malware, steal sensitive information, or maintain persistent access to compromised systems. The memory corruption nature of the flaw means that successful exploitation can result in complete system compromise, as attackers can manipulate memory contents to redirect execution flow or inject malicious payloads directly into running processes. This vulnerability affects not only individual users but also enterprise environments where Internet Explorer remains in use, creating widespread potential for security incidents across various organizations.
Organizations and security professionals should implement multiple layers of defense to protect against this vulnerability, including immediate patch deployment, browser hardening, and network-based protections. Microsoft released security updates addressing this vulnerability, but organizations must ensure comprehensive deployment across all affected systems. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write conditions, both of which are common patterns in memory corruption exploits. From an ATT&CK framework perspective, this vulnerability maps to techniques involving exploitation of known vulnerabilities and privilege escalation, making it particularly dangerous for threat actors seeking to establish persistent access to target systems. Effective mitigation requires both immediate remediation through security patches and ongoing monitoring for signs of exploitation attempts.