CVE-2017-0037: Microsoft Edge and Internet Explorer Type Confusion Vulnerability

CVE-2017-0037 is a type confusion vulnerability in Microsoft Edge and Internet Explorer, specifically in mshtml.dll. It can allow remote code execution if an attacker successfully triggers the flaw. For IT and security teams, this matters because browsers are common entry points; a successful exploit could let an attacker run code in the context of the logged-on user.

Public detail is limited to the vendor and CISA descriptions. Confirm exact affected builds, patch identifiers, and any configuration notes directly against the Microsoft advisory before acting.

How it works

The weakness is classified as CWE-704 (Incorrect Type Conversion or Cast). In this class of flaw, the browser’s rendering component mishandles an object’s type. When code later treats that object as a different type than it actually is, memory corruption or unexpected control flow can occur.

According to the CISA summary, the type confusion resides in mshtml.dll and can lead to remote code execution. An attacker would typically need to entice a user to open crafted web content in a vulnerable Edge or Internet Explorer instance. Beyond that high-level description, exploit mechanics are not provided here; treat any public proof-of-concept claims with caution and validate against the vendor advisory.

Am I affected? How to find it in your systems

Microsoft Edge and Internet Explorer are the affected products. These browsers commonly appear on Windows desktops, laptops, and some server or VDI images used for legacy web apps.

• Inventory Windows endpoints and identify installed browser versions (Edge legacy/EdgeHTML-era builds and Internet Explorer) via your software asset management, SCCM/ConfigMgr, Intune, or equivalent inventory tools.
• Check which systems still have Internet Explorer enabled or set as a default handler for intranet or legacy sites.
• Confirm the precise affected versions and fixed builds only from the Microsoft security advisory for CVE-2017-0037; do not rely on third-party version lists.
• For exploitation signs, review endpoint detection logs, browser crash reports involving mshtml.dll, and unusual child processes spawned from browser processes. There is no unique public indicator set provided in the given facts, so tune detections to your EDR’s browser-related behavioral rules and correlate with web-content delivery.

How to remediate

Patch first. Apply the updates Microsoft released for this vulnerability, following the vendor instructions referenced by CISA (“Apply updates per vendor instructions”). Use your standard patch-deployment pipeline and verify installation success across the estate.

• After patching, validate that the browser components report the fixed versions listed in the advisory.
• Where Internet Explorer is no longer required, disable or remove it and migrate users to a currently supported browser to shrink the attack surface for this class of rendering-engine flaws.
• Keep Windows and browser automatic update channels healthy so subsequent mshtml and browser security fixes are applied promptly.
• Enforce least privilege so that even if code execution occurs, the impact is limited to a standard user context rather than administrative rights.

If you can't patch immediately

Until the vendor update can be deployed, reduce exposure with compensating controls appropriate to browser type-confusion and remote-code-execution risks:

• Segment and restrict high-risk user populations from browsing untrusted sites; prefer isolated browsing environments or remote browser isolation where available.
• Use application control or attack-surface reduction rules to limit what browser processes can spawn and to block common post-exploit behaviors.
• If a web application firewall or secure web gateway is in use, enable protections that target drive-by and malicious-script delivery; treat these as temporary virtual-patching aids only, not replacements for the official fix.
• Disable or restrict Internet Explorer where business needs allow, and ensure Enhanced Protected Mode / relevant sandbox settings remain enabled.
• Heighten monitoring on endpoints still running the vulnerable browsers: alert on mshtml-related crashes, unexpected network connections from browser processes, and credential or lateral-movement activity following web browsing.

If your data may have been exposed

Actively exploited browser remote-code-execution vulnerabilities can lead to endpoint compromise and subsequent data theft or further intrusion. Known ransomware use is not documented for this CVE in the provided facts. If you suspect exploitation, follow your incident-response process: isolate affected hosts, preserve evidence, and hunt for persistence and data access. You can also run a free exposure scan of your email addresses against known breach data to see whether credentials or personal information have appeared in prior breaches unrelated to this specific issue.