Windows 10 1607: Use-after-free in Windows Installer enables local privilege escalation
Summary
The Windows Installer component in Windows 10 Version 1607 and Windows Server 2016 contains a use-after-free flaw (CWE-416). A locally authorized attacker can exploit it to elevate privileges on the affected system. Exploitation requires local access, a low-privileged account and a high-complexity condition, and the flaw is not directly reachable from the internet.
Affected
- Windows 10 Version 1607 (builds below 10.0.14393.9612), according to the CNA record
- Windows Server 2016 (builds below 10.0.14393.9612), according to the CNA record
- The CNA record also lists other Windows 10, Windows 11 and Windows Server 2012/2012 R2 builds
Fixed in
- Build 10.0.14393.9612 (KB5126868, released October 13, 2026), according to Microsoft's KB page
- Verify on MSRC whether the later build 10.0.14393.9615 (KB5134123) changes the fix, and whether KB5126868 covers this CVE, as one third-party listing does not show it
Workaround
Unknown. No workaround was found; apply the update.
Exploitation
- CISA SSVC: exploitation none, not automatable, total technical impact
- No known exploitation in the wild and no public proof of concept found
- EPSS 0.00252 (low)
Our recommendation
- Identify all Windows 10 1607 and Windows Server 2016 hosts, including their build number
- Install KB5126868 or the latest build that MSRC lists for this CVE
- Restrict local logon and administrative rights on legacy hosts until they are patched
- Plan a migration: Windows 10 1607 may stop receiving security updates, so confirm its lifecycle status with Microsoft
Information from Microsoft (Patch Tuesday October 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)
- KB5127648, KB5126651, KB5126655, KB5126657, KB5126646, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-70272 msrc.microsoft.com
- KB5126868: Windows 10 1607 security update support.microsoft.com
- NVD record via Vulners: CVE-2026-70272 vulners.com
- OpenCVE: CVE-2026-70272 app.opencve.io
- Windows 10 KB5126657 October 2026 update details www.it-connect.tech
- Patch Tuesday October 2026 listing (ManageEngine) pitstop.manageengine.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 4 Nov 2026, 08:52.
Original description (NVD)
Use after free 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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