Windows Installer: Local privilege escalation through type confusion
Summary
A type confusion flaw in Windows Installer allows an attacker who already has a local, low-privileged logon to elevate privileges, potentially to SYSTEM. The attack is local (AV:L, PR:L, no user interaction), so it is a post-foothold escalation rather than an internet-facing entry point. Impact is rated high for confidentiality, integrity and availability.
Affected
- Windows 10 Version 1607 (before 10.0.14393.9688)
- Windows 10 Version 1809 (before 10.0.17763.9487)
- Windows 10 Version 21H2 (before 10.0.19044.7846)
- Windows 10 Version 22H2 (before 10.0.19045.7846)
- Windows 11 Version 23H2 (before 10.0.22631.7711)
- Windows 11 Version 24H2 (before 10.0.26100.9974)
- Windows 11 Version 25H2 (before 10.0.26200.9974)
- Windows 11 Version 26H1 (before 10.0.28000.3501)
- Windows 11 Version 26H2 (before 10.0.26300.9974)
- Windows Server 2016 incl. Server Core (before 10.0.14393.9688)
- Windows Server 2019 incl. Server Core (before 10.0.17763.9487)
- Windows Server 2022 (before 10.0.20348.5870)
Fixed in
- Fixed in Microsoft's November 2026 security updates for the affected branches.
- The fixed builds are the versions listed as 'before' above (per the CVE record).
- The KB number per build is unknown. Confirm it in the MSRC Security Update Guide.
Workaround
Unknown.
Exploitation
- Exploited in the wild: none known at publication.
- Public proof of concept: none found.
- CISA KEV listing: not verified.
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
Our recommendation
- Install the November 2026 cumulative updates on all affected Windows 10, 11 and Server systems, starting with multi-user systems such as terminal and file servers and shared workstations.
- Confirm the exact fixed build per branch in the MSRC entry.
- Reduce local administrator rights and remove unnecessary local logons.
- Identify systems on Windows builds that no longer receive updates and plan their replacement or upgrade.
- Recheck KEV and proof-of-concept status in the coming days.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Installer
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5132061, KB5132043, KB5131085, KB5131090, KB5131096, KB5131080
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-96028 msrc.microsoft.com
- CVE Record CVE-2026-96028 (CVE.org) www.cve.org
- Strix: CVE-2026-96028 (secondary source) www.strix.ai
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, 02:46.
Original description (NVD)
Access of resource using incompatible type ('type confusion') in Windows Installer allows an authorized attacker to elevate privileges locally.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.