CVE-2018-8373 Microsoft Scripting Engine Memory Corruption Vulnerability
A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 25 Mar 2022.
- Rated High severity (CVSS 7.5, scored by CISA).
- It has been in the catalogue for 1,687 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer, aka "Scripting Engine Memory Corruption Vulnerability." This affects Internet Explorer 9, Internet Explorer 11, Internet Explorer 10. This CVE ID is unique from CVE-2018-8353, CVE-2018-8355, CVE-2018-8359, CVE-2018-8371, CVE-2018-8372, CVE-2018-8385, CVE-2018-8389, CVE-2018-8390.
Affected Versions
| Product | Versions |
|---|---|
| Microsoft Internet Explorer 9 | Windows Server 2008 for 32-bit Systems Service Pack 2 Windows Server 2008 for x64-based Systems Service Pack 2 |
| Microsoft Internet Explorer 11 | Windows 10 for 32-bit Systems Windows 10 for x64-based Systems Windows 10 Version 1607 for 32-bit Systems Windows 10 Version 1607 for x64-based Systems Windows 10 Version 1703 for 32-bit Systems Windows 10 Version 1703 for x64-based Systems |
| Microsoft Internet Explorer 10 | Windows Server 2012 |
From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for Microsoft Internet Explorer Scripting Engine. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
- 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
Vendor Advisories
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
Not Sure If You Are Exposed?
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