Windows DFS: Elevation of privilege via out-of-bounds read
Summary
An out-of-bounds read in the Windows Distributed File System (DFS) allows an authorized local attacker to elevate privileges. The CVSS rating is 7.8 (High), with high impact on confidentiality, integrity and availability. The attacker needs a local account or code execution, but no user interaction, so this is a second-stage risk and not an internet-facing flaw.
Affected
- Windows 11 version 23H2: 10.0.22631.0 before 10.0.22631.7711
- Windows 11 version 24H2: 10.0.26100.0 before 10.0.26100.9974
- Windows 11 version 25H2: 10.0.26200.0 before 10.0.26200.9974
- Windows 11 version 26H1: 10.0.28000.0 before 10.0.28000.3501
- Windows 11 version 26H2: 10.0.26300.0 before 10.0.26300.9974
- Windows Server 2025 (including Server Core): 10.0.26100.0 before 10.0.26100.33822 (verify against MSRC)
- Other Windows Server versions: Unknown.
Fixed in
- Install the November 2026 cumulative update for the affected versions, which provides builds at or above the numbers listed above.
- KB article numbers: Unknown.
Workaround
Unknown. No Microsoft or third-party mitigation is known. Patching is the expected remedy.
Exploitation
- No evidence of in-the-wild exploitation found.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- No public proof of concept found.
- NVD status at the time of analysis: Awaiting Analysis.
Our recommendation
- Apply the November 2026 cumulative updates to Windows 11 and Windows Server 2025 systems, prioritising file servers with DFS roles and terminal servers.
- Check MSRC for any other Windows Server versions and verify the Server 2025 build numbers.
- Restrict local logon on shared and multi-user systems and monitor for unexpected privilege changes.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Distributed File System (DFS)
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows
- Updates (KB)
- KB5131087, KB5132061, KB5132043, KB5131080, KB5131077, KB5132059
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Response Center: CVE-2026-118142 msrc.microsoft.com
- CVE.org record CVE-2026-118142 www.cve.org
- Strix: CVE-2026-118142 www.strix.ai
- Rapid7: Patch Tuesday November 2026 www.rapid7.com
- NewsBeep: November 2026 release www.newsbeep.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, 04:01.
Original description (NVD)
Out-of-bounds read in Windows Distributed File System (DFS) 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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