Microsoft Windows Installer: Local privilege escalation via missing authorization

Summary

Improper access control in the Windows Installer component allows a locally authorized user to elevate privileges. The CVSS vector rates the impact as high for confidentiality, integrity and availability, with low privileges required and no user interaction. Exploitation requires a local logon or an existing low-privilege foothold on the system.

Affected

• Windows 10 Version 1607 (10.0.14393.0 to before 10.0.14393.9688)
• Windows 10 Version 1809 (10.0.17763.0 to before 10.0.17763.9487)
• Windows 10 Version 21H2 (10.0.19044.0 to before 10.0.19044.7846)
• Windows 10 Version 22H2 (10.0.19045.0 to before 10.0.19045.7846)
• Windows 11 Version 23H2 (10.0.22631.0 to before 10.0.22631.7711)
• Windows 11 Version 24H2 (10.0.26100.0 to before 10.0.26100.9974)
• Windows 11 Version 25H2 (10.0.26200.0 to before 10.0.26200.9974)
• Windows 11 Version 26H1 (10.0.28000.0 to before 10.0.28000.3501)
• Windows 11 Version 26H2 (10.0.26300.0 to before 10.0.26300.9974)
• Windows Server 2016 incl. Server Core installation (10.0.14393.0 to before 10.0.14393.9688)
• Windows Server 2019 incl. Server Core installation (10.0.17763.0 to before 10.0.17763.9487)
• Windows Server 2022 (10.0.20348.0 to before 10.0.20348.5870)

Fixed in

• Install the cumulative update for each affected build that brings the build number to the listed fixed build or higher.
• Fixed builds per the CVE record: 10.0.14393.9688, 10.0.17763.9487, 10.0.19044.7846, 10.0.19045.7846, 10.0.22631.7711, 10.0.26100.9974, 10.0.26200.9974, 10.0.28000.3501, 10.0.26300.9974, 10.0.20348.5870.
• Security update (KB) numbers: Unknown. Check the MSRC advisory.

Workaround

Unknown.

Exploitation

• CISA SSVC assessment: exploitation none, not automatable, total technical impact.
• No public proof of concept or in-the-wild exploitation was found in the sources reviewed at publication.
• NVD status at publication: Awaiting Analysis.

Our recommendation

• Patch all listed Windows clients and servers with the November 2026 security update, prioritising multi-user systems, terminal servers and shared PCs.
• Check whether Windows 10 1607 and 1809 systems are still supported in your fleet, as they may not receive this fix through normal channels.
• Verify the KB number for each build on the MSRC advisory before rollout and confirm the fixed build after installation.
• Limit local administrator rights and monitor for unexpected installer activity until patched.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• CVE Record CVE-2026-96029 www.cve.org
• Microsoft Security Update Guide CVE-2026-96029 msrc.microsoft.com

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 02:47.