Microsoft Internet Explorer Use-After-Free Vulnerability
Microsoft Internet Explorer contains an use-after-free vulnerability that could allow remote attackers to execute arbitrary code by accessing a pointer associated with a deleted object. The impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization.
Quick answer
Microsoft Internet Explorer should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- 5.0.1
- 6
- -
- 7.0
- 8
- r2
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
CVE-2010-0249 is a legacy Internet Explorer remote code execution risk. The safest fix is to eliminate Internet Explorer use; where legacy compatibility is unavoidable, apply the Microsoft patch, lock browsing to approved internal sites, and isolate any remaining exposure.
- Inventory systems that can still run Internet Explorer or embedded IE controls.
- Apply the Microsoft security update that remediates CVE-2010-0249, or move the endpoint to a supported Windows and browser release.
- Block Internet Explorer from accessing the public internet using endpoint policy, proxy policy, and application control.
- Move required legacy sites to Microsoft Edge IE mode with a limited enterprise mode site list.
- Disable unnecessary ActiveX controls, scripting, browser helper objects, and automatic file handling.
- Run users without local administrator rights and isolate legacy browsing in a disposable VM or segmented environment if it must remain.
- Hunt for suspicious iexplore.exe child processes, unexpected downloads, and outbound connections from systems that were exposed.
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Verify the fix
- Verify patch inventory or OS replacement status for every endpoint in scope.
- Confirm IE cannot browse arbitrary external URLs after policy enforcement.
- Validate Edge IE mode is limited to the documented internal application list only.
- Review proxy and EDR logs for exploit-like browsing behavior or unexpected process creation.
- Retest the public website and legacy access flow with Fixnx after mitigation.
Related categories
Trusted references
FAQ
What is affected by CVE-2010-0249?
Microsoft Internet Explorer versions listed as affected should be reviewed: 5.0.1, 6, -, 7.0, 8, r2.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
Why can this risk appear in multiple categories?
A vulnerability can belong to more than one platform or ecosystem. Fixnx keeps one canonical risk page while also listing it in every relevant category.