# CVE-2026-85358: Microsoft Windows Installer heap-based buffer overflow

Source: https://junglewise.ai/threats/cve-2026-85358-heap-based-buffer-overflow-in-windows-installer-allows-an  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-85358 · Severity: high · CVSS 7.8 · Published 2026-10-13

Windows Installer, a system component that installs and manages software on Windows computers, contains a heap buffer overflow vulnerability. An authorized user with local access can exploit this flaw to run arbitrary code with elevated system privileges, potentially compromising the entire computer.

Technologies: [Microsoft Windows Installer](https://junglewise.ai/threats/technologies/windows-installer). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-85358 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-85358 being exploited in the wild.

**How severe is CVE-2026-85358?** 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-2026-85358?** 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-2026-85358 attacked?** It is attacked with local access.

**Am I affected by CVE-2026-85358?** 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 can be triggered by an authenticated local attacker. The vulnerability allows memory corruption leading to privilege escalation from a standard user to system-level access. Exploitation requires local access and prior authentication on the target system.

## Affected products

- Microsoft Windows Installer

## Timeline

- 2026-10-13: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85358](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85358)

## Related threats

- [Microsoft Windows Installer stack-based buffer overflow](https://junglewise.ai/threats/cve-2026-96152-stack-based-buffer-overflow-in-windows-installer-allows-an)
- [Windows Installer heap-based buffer overflow allows privilege elevation](https://junglewise.ai/threats/cve-2026-96085-heap-based-buffer-overflow-in-windows-installer-allows-an)
- [Microsoft Windows Installer heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-96062-heap-based-buffer-overflow-in-windows-installer-allows-an)
- [Windows Installer use-after-free privilege elevation](https://junglewise.ai/threats/cve-2026-96061-use-after-free-in-windows-installer-allows-an-authorized-attacker)
- [Windows Installer out-of-bounds read privilege escalation](https://junglewise.ai/threats/cve-2026-96060-out-of-bounds-read-in-windows-installer-allows-an-authorized)