Microsoft Windows Search: Elevation of privilege through use-after-free
Summary
A use-after-free vulnerability in the Windows Search Component allows an authorized local user to elevate privileges. An attacker needs an existing low-privilege account on the affected system and a high-complexity condition must be met. Successful exploitation could give the attacker full control of the host, as the impact on confidentiality, integrity and availability is rated high.
Affected
- Windows 10 Version 1607 (10.0.14393.0 before 10.0.14393.9612)
- Windows 10 Version 1809 (10.0.17763.0 before 10.0.17763.9376)
- Windows 10 Version 21H2 (10.0.19044.0 before 10.0.19044.7807)
- Windows 10 Version 22H2 (10.0.19045.0 before 10.0.19045.7807)
- Windows 11 Version 23H2 (10.0.22631.0 before 10.0.22631.7652)
- Windows 11 Version 24H2 (10.0.26100.0 before 10.0.26100.9711)
- Windows 11 Version 25H2 (10.0.26200.0 before 10.0.26200.9711)
- Windows 11 Version 26H1 (10.0.28000.0 before 10.0.28000.3231)
- Windows 11 Version 26H2 (10.0.26300.0 before 10.0.26300.9711)
- Windows Server 2012 and Server Core installation (6.2.9200.0 before 6.2.9200.26434)
- Windows Server 2012 R2 and Server Core installation (6.3.9600.0 before 6.3.9600.23470)
- Windows Server 2016 (10.0.14393.0 before 10.0.14393.9612)
Fixed in
- Install the Microsoft security update for CVE-2026-83574 that brings the build to the fixed version listed above or later.
- Fixed builds per the CNA record: 10.0.14393.9612 (1607, Server 2016), 10.0.17763.9376 (1809), 10.0.19044.7807 (21H2), 10.0.19045.7807 (22H2), 10.0.22631.7652 (23H2), 10.0.26100.9711 (24H2), 10.0.26200.9711 (25H2), 10.0.28000.3231 (26H1), 10.0.26300.9711 (26H2), 6.2.9200.26434 (Server 2012), 6.3.9600.23470 (Server 2012 R2).
- Third-party records name KB5126651 (1809, Server 2019) and KB5126646 (Server 2025). Verify these in the MSRC Update Guide.
- Some records give a different fixed build for Windows 11 24H2 (10.0.26100.33650). Verify this in the MSRC Update Guide.
Workaround
Unknown.
Exploitation
- CISA SSVC: exploitation none, not automatable.
- Not listed in the CISA KEV catalog.
- EPSS score very low (0.00307).
- No public proof of concept found in the research. This does not prove that none exists.
Our recommendation
- Install the Microsoft security update for CVE-2026-83574 on all affected Windows systems through Windows Update or WSUS.
- Inventory all Windows systems by build number, including Windows 10 1607 and 1809 and Windows Server 2012, 2012 R2 and 2016. Check whether each edition still receives security updates, and plan an upgrade where it does not.
- Prioritise multi-user systems, Remote Desktop hosts and file servers, because a local low-privilege account is enough to start the attack.
- Confirm that Windows Update is running and successful on all endpoints.
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)
- 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-2026-83574 msrc.microsoft.com
- Vulners CVE list entry CVE-2026-83574 vulners.com
- Vulners NVD entry CVE-2026-83574 vulners.com
- OpenCVE entry CVE-2026-83574 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 4 Nov 2026, 08:42.
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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