Windows Internet Connection Sharing: Out-of-bounds read leads to privilege escalation
Summary
Windows Internet Connection Sharing (ICS) contains an out-of-bounds read flaw (CWE-125) that allows an authorized local attacker to elevate privileges. The attacker needs a low-privileged local account and must overcome high attack complexity, and no user interaction is required. Successful exploitation could affect confidentiality, integrity and availability. Microsoft's CVE record gives no evidence of exploitation in the wild or of a public proof of concept.
Affected
- Windows 10 Version 1607 and Windows Server 2016 (including Server Core): builds before 10.0.14393.9688
- Windows 10 Version 1809 and Windows Server 2019 (including Server Core): builds before 10.0.17763.9487
- Windows 10 Version 21H2: builds before 10.0.19044.7846
- Windows 10 Version 22H2: builds before 10.0.19045.7846
- Windows 11 Version 23H2: builds before 10.0.22631.7711
- Windows 11 Version 24H2 and 25H2: builds before 10.0.26100.9974 and 10.0.26200.9974
- Windows 11 Version 26H1: builds before 10.0.28000.3501
- Windows 11 Version 26H2: builds before 10.0.26300.9974
- Windows Server 2022: builds before 10.0.20348.5870
Fixed in
Fixed in the November 2026 Patch Tuesday cumulative updates for the builds listed above. Verify the exact KB number for each OS in the Microsoft Security Update Guide.
Workaround
Unknown.
Exploitation
- Exploitation in the wild: none known.
- Public proof of concept: none found.
- CISA SSVC assessment: exploitation none, not automatable, total technical impact.
Our recommendation
- Confirm the affected builds in the Microsoft Security Update Guide and install the November 2026 updates on all affected systems.
- Prioritise multi-user systems such as terminal servers, RDS hosts, shared workstations and file servers.
- Check whether Windows 10 1607 and 1809 systems are still supported before planning their update.
- Monitor for a public proof of concept or a CISA KEV listing, which would raise the priority.
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, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131291, KB5131085, KB5131096, KB5131090, KB5131087, KB5132061
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-118124 msrc.microsoft.com
- CVE.org CNA record CVE-2026-118124 www.cve.org
- Strix mirror of CVE-2026-118124 (not authoritative) www.strix.ai
- BleepingComputer: Microsoft November 2026 Patch Tuesday www.bleepingcomputer.com
- Rapid7: Patch Tuesday November 2026 www.rapid7.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, 08:55.
Original description (NVD)
Out-of-bounds read 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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