CVE-2026-58634 in Microsoft Windows
Use after free in Desktop Window Manager allows an authorized attacker to elevate privileges locally.
Quick answer
Microsoft Windows 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
- Windows 11 26H1 before 10.0.28000.2525
Fixed versions
- Windows 11 26H1 10.0.28000.2525 or later
How to fix it
CVE-2026-58634 is a privilege escalation issue in Microsoft Windows. Update from Windows 11 26H1 before 10.0.28000.2525 to Windows 11 26H1 10.0.28000.2525 or later or newer. Keep it simple: upgrade first, then test the normal user flow.
- Find every place where Microsoft Windows is installed or used.
- Upgrade Microsoft Windows to Windows 11 26H1 10.0.28000.2525 or later or a newer fixed release from the vendor.
- If you cannot upgrade right away, limit access to the affected feature until the update is done.
- Restart or redeploy the service if the product needs it after the update.
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Verify the fix
- Confirm the installed version is Windows 11 26H1 10.0.28000.2525 or later or newer.
- Run a normal login, admin, and user flow to make sure the site still works.
- Check logs for new errors after the update.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-58634?
Microsoft Windows versions listed as affected should be reviewed: Windows 11 26H1 before 10.0.28000.2525.
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.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.