Actively exploited

CVE-2013-3893 Microsoft Internet Explorer Resource Management Errors Vulnerability

Microsoft Internet Explorer contains a memory corruption vulnerability that allows for remote code execution. The impacted products could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch urgentlyCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 12 Aug 2025.
  • Rated High severity (CVSS 8.8, scored by CISA).
  • It has been in the catalogue for 451 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

Use-after-free vulnerability in the SetMouseCapture implementation in mshtml.dll in Microsoft Internet Explorer 6 through 11 allows remote attackers to execute arbitrary code via crafted JavaScript strings, as demonstrated by use of an ms-help: URL that triggers loading of hxds.dll.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Microsoft Internet Explorer. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

    Vulnerability Management
  3. 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. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Not Sure If You Are Exposed?

Our attack surface and vulnerability teams can check your internet-facing estate for CVE-2013-3893 and every other exploited flaw on the list.

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