CVE-2026-87700: Windows Installer use-after-free privilege escalation

CVE-2026-87700 · Severity: high · CVSS 7.8 · Published 2026-10-13

Windows Installer, a core component responsible for software installation on Windows systems, contains a use-after-free vulnerability that allows an authorized local user to escalate their privileges to a higher level of access. An attacker with local system access could exploit this flaw to gain administrative rights and take full control of the compromised computer.

Technologies: Microsoft Windows Installer. Vendors: Microsoft.

Quick answers

Is CVE-2026-87700 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-87700 being exploited in the wild.
How severe is CVE-2026-87700?
High severity, with a CVSS score of 7.8, published 13 October 2026.
Which products and versions are affected?
Microsoft Windows Installer.
Is there a fix for CVE-2026-87700?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-87700 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2026-87700?
Check whether you run Microsoft Windows Installer. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A use-after-free memory safety vulnerability exists in Windows Installer that can be triggered by an authorized local attacker. The vulnerability requires local access and existing user privileges; successful exploitation grants privilege escalation to a higher privilege level on the affected system.

Affected products

  • Microsoft Windows Installer

Timeline

  • 2026-10-13: disclosed

References

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