Windows Installer: Elevation of privilege via integer overflow
Summary
Microsoft has published CVE-2026-96036 for Windows Installer, the built-in Windows component that installs, repairs and removes MSI packages. An integer overflow or wraparound can be triggered by an authorized local user, allowing privilege escalation to higher rights on the host. Exploitation requires local access and a low-privileged account, so the flaw is typically relevant after an initial compromise.
Affected
- Windows 10 Version 1607 (10.0.14393.0 before 10.0.14393.9688)
- Windows 10 Version 1809 (10.0.17763.0 before 10.0.17763.9487)
- Windows 10 Version 21H2 (10.0.19044.0 before 10.0.19044.7846)
- Windows 10 Version 22H2 (10.0.19045.0 before 10.0.19045.7846)
- Windows 11 Version 23H2 (10.0.22631.0 before 10.0.22631.7711)
- Windows 11 Version 24H2 (10.0.26100.0 before 10.0.26100.9974)
- Windows 11 Version 25H2 (10.0.26200.0 before 10.0.26200.9974)
- Windows 11 Version 26H1 (10.0.28000.0 before 10.0.28000.3501)
- Windows 11 Version 26H2 (10.0.26300.0 before 10.0.26300.9974)
- Windows Server 2016 including Server Core (10.0.14393.0 before 10.0.14393.9688)
- Windows Server 2019 including Server Core (10.0.17763.0 before 10.0.17763.9487)
- Windows Server 2022 (10.0.20348.0 before 10.0.20348.5870)
Fixed in
Fixed in the security update for each listed build, i.e. builds at or above the fixed version listed above. KB article numbers: Unknown; see the MSRC page.
Workaround
Unknown. No vendor-documented workaround found. Install the security update.
Exploitation
- No known exploitation in the wild found at the time of writing.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- CVSS temporal exploit maturity: Unproven.
- No public proof of concept found.
Our recommendation
- Install the Microsoft security update on all affected Windows clients and servers, starting with shared, terminal and admin workstations.
- Identify systems still on Windows 10 1607, 1809 or 21H2 and check their support status.
- Restrict local admin rights and monitor for unexpected MSI installations and privilege changes.
- Recheck CISA KEV and vendor sources before final prioritisation.
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-2026-96036 msrc.microsoft.com
- CVE Record CVE-2026-96036 (CVE Program) www.cve.org
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, 02:44.
Original description (NVD)
Integer overflow or wraparound 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.
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