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CVE-2026-85796 Microsoft CVE debrief

A numeric truncation error in Windows Installer allows an authorized attacker to elevate privileges locally. Multiple Windows versions are affected, including Windows 10, Windows 11, and Windows Server. This vulnerability has a high severity and requires immediate attention from system administrators and security teams. The affected products include Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 version 23H2, Windows 11 Version 23H2, Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, Windows 11 Version 26H2, Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-13
Original CVE updated
2026-10-13
Advisory published
2026-10-13
Advisory updated
2026-10-13

Who should care

System administrators and security teams responsible for Windows systems should assess exposure and apply patches immediately to prevent local privilege elevation.

Why it matters

CVE-2026-85796 is a high-severity vulnerability in Windows Installer that allows local privilege elevation. System administrators and security teams should assess exposure and apply patches immediately to prevent exploitation.

  • Local privilege elevation can lead to system compromise
  • Patching is required to prevent exploitation
  • Verify Windows versions and apply updates
  • Monitor for suspicious activity

Technical summary

The Windows Installer Elevation of Privilege Vulnerability (CVE-2026-85796) is caused by a numeric truncation error. An authorized attacker can exploit this vulnerability to elevate privileges locally. Affected products include Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 version 23H2, Windows 11 Version 23H2, Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, Windows 11 Version 26H2, Windows Server 2012, Windows Server 2012 (Server Core installation), Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation), Windows Server 2016, Windows Server 2016 (Server Core installation), Windows Server 2019, Windows Server 2019 (Server Core installation), Windows Server 2022, and Windows Server 2025.

Defensive priority

Apply patches immediately for Windows Installer to prevent local privilege elevation.

Recommended defensive actions

  • Apply patches for Windows Installer
  • Verify and update Windows versions
  • Monitor for local privilege elevation attempts

Evidence notes

The CVE Program and NVD provide official records of the vulnerability. Microsoft has released a patch for the issue. The vulnerability affects multiple Windows versions, including Windows 10, Windows 11, and Windows Server. System administrators and security teams should assess exposure and apply patches immediately to prevent local privilege elevation. The official CVE Program record and NIST NVD detail page provide source-specific vulnerability assessment and guidance.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-85796 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-85796

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-85796 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-85796

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Windows Installer Elevation of Privilege Vulnerability

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/85xxx/CVE-2026-85796.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85796

    Supplemental source - vendor-advisory, patch

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.