Microsoft Windows Installer: Elevation of privilege via incorrect authorization
Summary
Incorrect authorization in the Windows Installer component allows an authorized local attacker to elevate privileges on affected Windows 10, Windows 11 and Windows Server systems. An attacker needs a local account or an existing foothold on the system, but no user interaction is required. Successful exploitation can lead to full control over the affected system.
Affected
- Windows 10 Version 1607, 1809, 21H2, 22H2
- Windows 11 Version 23H2, 24H2, 25H2, 26H1, 26H2
- Windows Server 2016, 2019, 2022 (including Server Core installations)
- Exact affected builds: see the MSRC Security Update Guide (the CVE record lists builds below 10.0.14393.9688, 10.0.17763.9487, 10.0.19044.7846, 10.0.19045.7846, 10.0.22631.7711, 10.0.20348.5870, 10.0.26100.9974, 10.0.26200.9974, 10.0.28000.3501 and 10.0.26300.9974)
Fixed in
- Security update released on 10 November 2026 for the affected Windows versions
- 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, 10.0.20348.5870, 10.0.26100.9974, 10.0.26200.9974, 10.0.28000.3501, 10.0.26300.9974
- KB mapping: unverified, confirm on MSRC
Workaround
Unknown.
Exploitation
- Microsoft assessment: Exploitation More Likely
- Public proof of concept: none found
- Exploited in the wild: no evidence found
- CISA SSVC: Exploitation none, not automatable, total technical impact
Our recommendation
- Install the November 2026 Windows security update on all affected systems, prioritising servers and multi-user machines such as terminal servers
- Confirm the correct KB for each OS version on the MSRC page before rollout
- Limit local logon and software installation rights to necessary users
- Monitor for proof-of-concept or exploitation reports and recheck the exploitability status after a few days
- Check NVD for the final scoring, as it was still awaiting analysis at the time of research
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 more 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 Update Guide: CVE-2026-105501 msrc.microsoft.com
- CVE Record: CVE-2026-105501 www.cve.org
- Tenable: Microsoft November 2026 Patch Tuesday www.tenable.com
- Talos: Microsoft Patch Tuesday for November 2026 blog.talosintelligence.com
- Strix: CVE-2026-105501 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, 04:36.
Original description (NVD)
Incorrect authorization 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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