CVE-2016-3386 in Edge
Summary
by MITRE
The Chakra JavaScript engine in Microsoft Edge allows 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-2016-3389, CVE-2016-7190, and CVE-2016-7194.
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Analysis
by VulDB Data Team • 02/28/2025
The vulnerability identified as CVE-2016-3386 represents a critical memory corruption flaw within Microsoft Edge's Chakra JavaScript engine, which serves as the core execution environment for JavaScript code in the browser. This vulnerability specifically affects the scripting engine's handling of memory management during JavaScript execution, creating a pathway for remote code execution attacks. The flaw manifests when malicious web content triggers improper memory operations within the Chakra engine, potentially leading to arbitrary code execution or system crashes. The vulnerability is particularly concerning because it operates at the JavaScript engine level, meaning that a successful exploitation could allow attackers to bypass traditional browser security boundaries and gain control over the underlying system.
The technical nature of this vulnerability stems from improper memory handling within the Chakra JavaScript engine's memory allocation and deallocation processes. When processing maliciously crafted JavaScript code, the engine fails to properly validate memory operations, leading to buffer overflows, use-after-free conditions, or other memory corruption scenarios. These memory corruption issues can be exploited by attackers who craft specific web pages containing malicious JavaScript code designed to trigger the vulnerable code paths. The vulnerability is classified under CWE-125 as an out-of-bounds read condition and may also relate to CWE-787 as an out-of-bounds write condition, depending on the specific memory corruption pattern. Attackers can leverage this vulnerability through various attack vectors including phishing websites, malicious advertisements, or compromised web applications that deliver the exploit code directly to the victim's browser.
The operational impact of CVE-2016-3386 extends beyond simple denial of service scenarios, as it provides attackers with the capability to execute arbitrary code with the privileges of the Edge browser process. This means that successful exploitation could result in complete system compromise, data exfiltration, or installation of persistent malware. The vulnerability affects Microsoft Edge versions prior to the security updates released in July 2016, making it particularly dangerous for organizations that have not kept their systems up to date. The attack surface is broad since any user visiting a compromised website could be affected, and the exploit requires no user interaction beyond normal browsing behavior. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.007 for JavaScript and T1059.001 for command and scripting interpreter, as attackers can leverage the JavaScript engine's capabilities to execute malicious payloads directly within the browser environment.
Organizations should implement immediate mitigations including applying the relevant Microsoft security updates and patches released in the July 2016 security bulletin. Browser isolation techniques and network-based protections such as web application firewalls can provide additional layers of defense against exploitation attempts. Security teams should monitor for indicators of compromise related to this vulnerability, particularly focusing on unusual JavaScript execution patterns or memory access violations. The vulnerability also highlights the importance of keeping browser software up to date, as it demonstrates how flaws in core engine components can provide attackers with significant system access capabilities. Regular security assessments and penetration testing should include evaluation of browser-based attack surfaces, with particular attention to JavaScript engine vulnerabilities that could be exploited for privilege escalation or persistent access to target systems.