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CVE-2026-85830 Microsoft CVE debrief

A Windows Installer Information Disclosure Vulnerability exists due to an out-of-bounds read in Windows Installer. An authorized attacker can exploit this vulnerability locally to disclose information. This vulnerability affects Windows 10 versions 1607, 1809, 21H2, 22H2, Windows 11 versions 23H2, 24H2, 25H2, 26H1, 26H2, and various Windows Server versions. Defenders should assess exposure and apply patches immediately. The vulnerability allows for local information disclosure, emphasizing the need for prompt patching and verification of patch status for affected Windows versions.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
MEDIUM 5.5
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

Defenders responsible for Windows systems, particularly those managing Windows 10, Windows 11, and Windows Server environments, should assess exposure and apply patches. System administrators and security teams need to prioritize patching to prevent local information disclosure.

Why it matters

CVE-2026-85830 is a Windows Installer Information Disclosure Vulnerability. An authorized attacker can exploit this vulnerability locally to disclose information. Defenders should apply patches immediately, inventory and verify patch status for affected Windows versions, and monitor for suspicious activity.

  • Local information disclosure possible for authorized attackers
  • Patching required for Windows Installer to prevent exploitation
  • Verification of patch status necessary for affected Windows versions
  • Monitoring for suspicious activity recommended

Technical summary

The vulnerability exists due to an out-of-bounds read in Windows Installer. An authorized attacker can exploit this vulnerability locally to disclose information. Affected products include Windows 10 versions 1607, 1809, 21H2, 22H2, Windows 11 versions 23H2, 24H2, 25H2, 26H1, 26H2, and various Windows Server versions.

Defensive priority

Apply patches immediately for Windows Installer to prevent local information disclosure. Inventory and verify the patch status of Windows 10, Windows 11, and Windows Server versions listed in the affected products.

Recommended defensive actions

  • Apply patches for Windows Installer from Microsoft
  • Inventory and verify patch status for Windows 10, Windows 11, and Windows Server
  • Monitor Windows Installer for suspicious activity

Evidence notes

The CVE Program and NVD provide official records of the vulnerability. Microsoft's advisory confirms the vulnerability and provides patches for affected versions.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-85830 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-85830

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

  • CVE-2026-85830 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-85830

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

Supplemental references

  • Windows Installer Information Disclosure Vulnerability

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/85xxx/CVE-2026-85830.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85830

    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.