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 via vectors involving access to an invalid pointer after the deletion of an 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
- 5.01
- 6
- 8
- -
- r2
- 7
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
Retire Internet Explorer wherever possible. If a legacy system still depends on it, apply the Microsoft security update for CVE-2010-0806, remove direct internet exposure, disable risky browser features, and move the workflow to a supported browser or isolated compatibility environment.
- Identify every workstation, server image, kiosk, virtual desktop, and application workflow that can still launch Internet Explorer.
- Apply the relevant Microsoft Internet Explorer security update for CVE-2010-0806 or replace the host with a supported Windows and browser release.
- Remove Internet Explorer from normal user workflows and migrate required legacy applications to Microsoft Edge IE mode only where business-critical.
- Restrict any remaining IE mode sites to a strict enterprise site list; do not allow arbitrary internet browsing with Internet Explorer.
- Disable or tightly restrict ActiveX, scripting, browser helpers, unsafe file downloads, and automatic opening of untrusted content.
- Isolate legacy systems behind network controls, least-privilege accounts, EDR monitoring, and no direct email or web access.
- Treat any system that browsed untrusted content while unpatched as potentially compromised and review endpoint telemetry.
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Verify the fix
- Confirm the Microsoft update or supported replacement build is installed on every affected endpoint.
- Open the legacy workflow and verify it no longer permits arbitrary internet browsing through Internet Explorer.
- Check browser policy, ActiveX policy, and enterprise site list settings from endpoint management.
- Review EDR, proxy, and Windows event logs for suspicious IE process activity before and after remediation.
- Run a Fixnx scan and confirm no public site workflow depends on exposing the vulnerable legacy browser path.
Related categories
Trusted references
FAQ
What is affected by CVE-2010-0806?
Microsoft Internet Explorer versions listed as affected should be reviewed: 5.01, 6, 8, -, r2, 7.
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.