Microsoft Windows: Elevation of privilege via use after free in Windows Search
Summary
A use-after-free flaw in the Microsoft Windows Search component allows an authorized local user to elevate privileges. An attacker needs local access and low privileges, so the flaw is a privilege escalation step rather than an entry point. Successful exploitation could give the attacker SYSTEM rights on the affected machine. Microsoft rates exploitation as less likely, and no public exploit is known.
Affected
- Windows 10 Version 1607 (10.0.14393.0 to before 10.0.14393.9612)
- Windows 10 Version 1809 (10.0.17763.0 to before 10.0.17763.9376)
- Windows 10 Version 21H2 (10.0.19044.0 to before 10.0.19044.7807)
- Windows 10 Version 22H2 (10.0.19045.0 to before 10.0.19045.7807)
- Windows 11 Version 23H2 (10.0.22631.0 to before 10.0.22631.7652)
- Windows 11 Version 24H2 (10.0.26100.0 to before 10.0.26100.9711)
- Windows 11 Version 25H2 (10.0.26200.0 to before 10.0.26200.9711)
- Windows 11 Version 26H1 (10.0.28000.0 to before 10.0.28000.3231)
- Windows 11 Version 26H2 (10.0.26300.0 to before 10.0.26300.9711)
- Windows Server 2012 R2 incl. Server Core (6.3.9600.0 to before 6.3.9600.23470)
- Windows Server 2016 incl. Server Core (10.0.14393.0 to before 10.0.14393.9612)
- Windows Server 2019 (10.0.17763.0 to before 10.0.17763.9376)
- The NVD CPE list is incomplete and only names Windows 10 1607.
Fixed in
- Install the security update released for CVE-2026-83570 via Windows Update or WSUS.
- Fixed build for Windows 10 1607 and Server 2016 according to aggregators: 10.0.14393.9612. Verify on the MSRC page before deployment.
- KB number for Windows 10 1607: Unknown. Check the MSRC update table.
- Aggregators contain conflicting build numbers for some branches. Use the MSRC page as the reference.
Workaround
Unknown. No vendor-documented workaround was found. Install the update.
Exploitation
- Microsoft: not publicly disclosed, not exploited, exploitability assessment 'Exploitation Less Likely', exploit code maturity 'Unproven'.
- CISA SSVC: exploitation none, not automatable; not listed in KEV.
- EPSS: about 0.4%.
- No public proof of concept found. Keep monitoring, as absence in sources is not proof.
Our recommendation
- Inventory all Windows 10, Windows 11 and Windows Server systems and check their build numbers.
- Prioritise any Windows 10 1607 and Server 2016 systems still in service and check their Microsoft support status.
- Patch affected endpoints and servers in the normal cycle, with 1607 systems first.
- Limit local logon rights and monitor for unusual privilege escalation to SYSTEM.
- Re-assess priority if an exploit appears or the CVE is added to KEV.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Microsoft Windows Search Component
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5126651, KB5126655, KB5126657, KB5126646, KB5127648, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-83570 msrc.microsoft.com
- NVD mirror on Vulners: CVE-2026-83570 vulners.com
- OpenCVE: CVE-2026-83570 app.opencve.io
- Strix: CVE-2026-83570 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 2 Nov 2026, 03:40.
Original description (NVD)
Use after free in Microsoft Windows Search Component 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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