Microsoft Windows Search Component: Privilege escalation via heap overflow

Summary

The Microsoft Windows Search Component contains a heap-based buffer overflow that allows an authorized local user to elevate privileges. A successful attacker can gain SYSTEM-level rights, which affects confidentiality, integrity and availability. Exploitation requires local access with low privileges, and user interaction may be part of the attack chain. Microsoft has released fixes, and no public exploit or in-the-wild exploitation has been reported.

Affected

• Windows 10 Version 1607 and Windows Server 2016 (builds below 10.0.14393.9612)
• Windows 10 Version 1809 and Windows Server 2019 (builds below 10.0.17763.9376)
• Windows 10 Version 21H2 (builds below 10.0.19044.7807) and 22H2 (builds below 10.0.19045.7807)
• Windows 11 Version 23H2, 24H2, 25H2, 26H1, 26H2 and Windows Server 2012, 2012 R2 (builds as listed in the CNA record)
• Server Core installations are affected as well

Fixed in

• Windows 10 Version 1607 / Server 2016: 10.0.14393.9612 or later (per CNA record; KB number unknown, verify on the MSRC update guide)
• Windows 10 1809 / Server 2019: 10.0.17763.9376 or later
• Windows 10 21H2 / 22H2: 10.0.19044.7807 / 10.0.19045.7807 or later
• Other branches: see the MSRC update guide

Workaround

• No vendor workaround published. Patching is the primary remediation.
• A third-party source (OpenCVE) suggests stopping the Windows Search service if a patch cannot be applied. This is not a vendor recommendation and disables search and indexing features.

Exploitation

• No confirmed in-the-wild exploitation.
• VulDB reports that no technical details or exploit are publicly available.
• CISA SSVC: exploitation none, not automatable, total technical impact.
• EPSS is very low (0.00318).

Our recommendation

• Identify all Windows 10 1607 and Server 2016 systems and check whether they still receive security updates.
• Install the October 2026 cumulative update (or ESU) and verify the fixed build number on the MSRC update guide.
• Prioritize multi-user systems, terminal servers and shared workstations.
• Plan the upgrade of end-of-support systems; the patch gap is a larger risk than this single CVE.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• Microsoft Security Update Guide (CVE-2026-85869) msrc.microsoft.com
• Microsoft Security Update Guide (en-US) msrc.microsoft.com
• Vulners NVD mirror vulners.com
• VulDB entry vuldb.com
• OpenCVE app.opencve.io

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 2 Nov 2026, 01:48.