Microsoft Windows ICS: Elevation of privilege via use after free
Summary
A use-after-free flaw in the Windows Internet Connection Sharing (ICS) component allows an authorized local attacker to elevate privileges. An attacker needs an existing local account or session and must overcome high attack complexity. The flaw is not reachable from the internet, but a compromised user session could gain SYSTEM rights on an affected machine.
Affected
- Windows 11 Version 24H2: 10.0.26100.0 to before 10.0.26100.9974
- Windows 11 Version 25H2: 10.0.26200.0 to before 10.0.26200.9974
- Windows 11 Version 26H1: 10.0.28000.0 to before 10.0.28000.3501
- Windows 11 Version 26H2: 10.0.26300.0 to before 10.0.26300.9974 (third-party source, unverified)
- Windows Server 2025 (including Server Core): 10.0.26100.0 to before 10.0.26100.33822 (third-party source, unverified)
Fixed in
- Microsoft security update released on 2026-11-10 (November 2026 Patch Tuesday). Build-to-KB mapping not yet verified; third-party trackers list KB5132061 (24H2/25H2) and KB5132059 (26H1).
Workaround
- No workaround confirmed by a source. Apply the security update.
- Optional, own recommendation: disable ICS on hosts that do not need to share a connection.
Exploitation
- Not known to be exploited in the wild.
- No public proof of concept found; exploit maturity is rated Unproven.
- CISA SSVC: exploitation none, automatable no, technical impact total.
Our recommendation
- Install the November 2026 cumulative update on all affected Windows 11 and Server 2025 systems, with priority on multi-user, terminal and RDP servers.
- Verify the installed build against the Microsoft Security Update Guide.
- Disable Internet Connection Sharing where it is not required.
- Monitor for unusual privilege escalation on endpoints.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Internet Connection Sharing (ICS)
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows
- Updates (KB)
- KB5132061, KB5132043, KB5131080, KB5131077, KB5132059
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE.org record CVE-2026-119859 www.cve.org
- Microsoft Security Update Guide (not retrieved) msrc.microsoft.com
- Rapid7 November 2026 Patch Tuesday www.rapid7.com
- VulDB CVE-2026-119859 vuldb.com
- Strix CVE-2026-119859 www.strix.ai
- Senserva KB5132061 senserva.com
- Senserva KB5132059 senserva.com
- GBHackers November 2026 Patch Tuesday gbhackers.com
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 11 Nov 2026, 08:37.
Original description (NVD)
Use after free in Windows Internet Connection Sharing (ICS) 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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