Microsoft Windows Installer: Elevation of privilege through race condition
Summary
A race condition (CWE-362) and an untrusted pointer dereference (CWE-822) in Windows Installer allow an authorized local attacker to gain elevated privileges. The attacker needs a local account and must win a timing race, so the attack complexity is high. Successful exploitation could give the attacker full control over the local system.
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
- Install the November 2026 security update (Patch Tuesday) for the affected Windows builds, which contains builds at or above the versions listed above.
- Knowledge base article numbers: Unknown.
Workaround
Unknown.
Exploitation
- No evidence of in-the-wild exploitation was found.
- No public proof of concept was found.
- CVSS exploit code maturity is 'Unproven' (E:U).
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
Our recommendation
- Patch affected Windows 10, Windows 11 and Windows Server systems with the November 2026 update, prioritising multi-user systems, terminal servers and shared PCs.
- Limit local administrator rights and keep users on standard accounts where possible.
- Verify the affected version list and KB numbers on the MSRC advisory before rollout.
- Monitor NVD for its analysis and any CISA KEV addition.
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)
- KB5131291, KB5131085, KB5131096, KB5131090, KB5131087, KB5132061
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Response Center: CVE-2026-96019 msrc.microsoft.com
- CVE Record: CVE-2026-96019 www.cve.org
- Strix AI: CVE-2026-96019 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, 07:51.
Original description (NVD)
Concurrent execution using shared resource with improper synchronization ('race condition') 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.
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