CVE-2026-65774: Microsoft Windows Installer heap-based buffer overflow privilege escalation

CVE-2026-65774 · Severity: high · CVSS 7.8 · Published 2026-08-11

Windows Installer, a core component responsible for installing and managing software on Windows systems, contains a heap-based buffer overflow vulnerability. An authorized local attacker can exploit this flaw to execute code with elevated privileges, potentially gaining full control of the affected system and compromising all data and operations running on it.

Technologies: Microsoft Windows Installer. Vendors: Microsoft.

Quick answers

Is CVE-2026-65774 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-65774 being exploited in the wild.
How severe is CVE-2026-65774?
High severity, with a CVSS score of 7.8, published 11 August 2026.
Which products and versions are affected?
Microsoft Windows Installer.
Is there a fix for CVE-2026-65774?
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-2026-65774 attacked?
It is attacked with local access.
Am I affected by CVE-2026-65774?
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 heap-based buffer overflow exists in Windows Installer that allows a local, authenticated attacker to elevate privileges. The vulnerability requires the attacker to already have local access to the system. Exploitation results in arbitrary code execution with elevated privileges. A patch is available from Microsoft through the security update referenced in the advisory.

Affected products

  • Microsoft Windows Installer

Timeline

  • 2026-08-11: disclosed

References

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