Windows Network Connection Broker: Use-after-free leads to local privilege escalation
Summary
A use-after-free vulnerability (CWE-416) in the Windows Network Connection Broker component allows an authorized local user to elevate privileges. The attacker needs a low-privilege logon on the affected system, and attack complexity is high. The CVSS 3.1 base score is 7.0 (High), and the vulnerability cannot be exploited remotely over the network.
Affected
Per the official CVE record (third-party sources list different ranges, so verify on MSRC):
- Windows 10 Version 1607 and Windows Server 2016 (including Server Core): 10.0.14393.0 to before 10.0.14393.9688
- Windows 10 Version 1809 and Windows Server 2019 (including Server Core): 10.0.17763.0 to before 10.0.17763.9487
- Windows 10 Version 21H2: 10.0.19044.0 to before 10.0.19044.7846
- Windows 10 Version 22H2: 10.0.19045.0 to before 10.0.19045.7846
- Windows 11 Version 23H2: 10.0.22631.0 to before 10.0.22631.7711
- Windows 11 Version 24H2: 10.0.26100.0 to before 10.0.26100.9974
- Windows 11 Version 25H2 and 26H2: 10.0.26200.0 to before 10.0.26200.9974 (25H2) and 10.0.26300.0 to before 10.0.26300.9974 (26H2)
- Windows 11 Version 26H1: 10.0.28000.0 to before 10.0.28000.3501
- Windows Server 2022: 10.0.20348.0 to before 10.0.20348.5870
Fixed in
Install the November 2026 security update from Microsoft. Fixed builds per the official CVE record:
- 10.0.14393.9688 (Windows 10 1607, Server 2016)
- 10.0.17763.9487 (Windows 10 1809, Server 2019)
- 10.0.19044.7846 (Windows 10 21H2)
- 10.0.19045.7846 (Windows 10 22H2)
- 10.0.22631.7711 (Windows 11 23H2)
- 10.0.26100.9974 (Windows 11 24H2)
- 10.0.26200.9974 (Windows 11 25H2)
- 10.0.26300.9974 (Windows 11 26H2)
- 10.0.28000.3501 (Windows 11 26H1)
- 10.0.20348.5870 (Windows Server 2022)
Knowledge Base article numbers: Unknown.
Workaround
Unknown. No vendor workaround is known; patching is the remedy.
Exploitation
- Microsoft reports no publicly available exploit code and no known exploitation in the sources reviewed.
- CISA SSVC: exploitation none, automatable no.
- Not checked against the CISA KEV catalogue; recheck KEV and MSRC.
Our recommendation
- Install the November 2026 cumulative update on all affected systems, with priority on multi-user hosts such as Remote Desktop/terminal servers, shared workstations and file servers.
- Confirm the exact fixed build for each product on the MSRC advisory, as the sources conflict.
- Restrict local logons to trusted users and check for suspicious local accounts or malware.
- Recheck the CISA KEV catalogue and the NVD entry, which is currently awaiting analysis.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Network Connection Broker
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131085, KB5131090, KB5131096, KB5131080, KB5131077, KB5132061
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Response Center: CVE-2026-108406 msrc.microsoft.com
- CVE Record CVE-2026-108406 (CVE.org) www.cve.org
- Strix: CVE-2026-108406 (third-party, unverified ranges) www.strix.ai
- Patch Tuesday November 2026 coverage (Action1) www.action1.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, 09:31.
Original description (NVD)
Use after free in Windows Network Connection Broker 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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