CVE-2017-8640: Microsoft Edge scripting engine memory corruption allows code execution

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 19 September 2026. Confidence: medium.

high priorityRemote code execution in a widely deployed browser with public exploit code and very high EPSS, though exploitation requires user interaction and the affected platforms are legacy.

What it is

Microsoft Edge's JavaScript engine mishandles objects in memory, causing a memory corruption condition (CWE-119) when rendering content. A remote attacker can exploit this to run arbitrary code in the context of the current user, which matters because the browser is a common entry point for full user-level compromise.

Impact

An attacker gains arbitrary code execution with the privileges of the logged-in user, enabling data theft, persistence, or further lateral movement. Because the flaw is in the browser engine, successful exploitation can compromise the host without a separate privilege escalation step.

Attack surface

Reached over the network by a user visiting attacker-controlled or compromised web content in Microsoft Edge; the CVSS vector shows no privileges required but user interaction required (UI:R), so the victim must open the page. No authentication is needed.

Exploitation

Not listed in CISA KEV, but EPSS is very high (0.69277, 99.3rd percentile) and a public Exploit-DB entry (42476) exists, indicating exploit code is available. No ransomware group usage is documented.

What to do

• Apply the Microsoft security update referenced in the vendor advisory (portal.msrc.microsoft.com) for the affected Windows 10 and Windows Server 2016 builds.
• Upgrade to a currently supported Windows release and browser version, since the listed platforms (Gold, 1511, 1607, 1703) are long out of support.
• Enforce browser hardening such as Enhanced Mitigation Experience Toolkit/Exploit Protection and disable unnecessary scripting where feasible.
• Restrict or block access to untrusted web content and use network filtering to reduce exposure to exploit-hosting sites.

Detection

• Monitor for Edge (MicrosoftEdge.exe) crashes or abnormal child process creation, which can indicate memory corruption exploitation.
• Alert on suspicious post-browser process chains, such as a browser process spawning scripting hosts, PowerShell, or cmd.
• Hunt for known exploit artifacts tied to Exploit-DB 42476 and related scripting-engine PoCs in web proxy or endpoint telemetry.
• Correlate endpoint telemetry for browser exploitation indicators with outbound connections to newly seen or low-reputation hosts.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.