Windows Server (Server for NFS): Information disclosure vulnerability
Summary
A improper access control flaw in the Server for NFS component of Windows Server allows an authorized local user to read information they should not see. Only confidentiality is affected, and the attacker needs local access and a low-privilege account. The risk is mainly relevant for NFS file servers that serve sensitive data.
Affected
- Windows Server 2016 and Server Core installation: 10.0.14393.0 to before 10.0.14393.9688
- Windows Server 2019 and Server Core installation: 10.0.17763.0 to before 10.0.17763.9487
- Windows Server 2022: 10.0.20348.0 to before 10.0.20348.5870
- Windows Server 2025 and Server Core installation: 10.0.26100.0 to before 10.0.26100.33822 (listed in the CVE record excerpt and one mirror; verify with MSRC)
Fixed in
- Windows Server 2016 and Server Core: build 10.0.14393.9688 or later
- Windows Server 2019 and Server Core: build 10.0.17763.9487 or later
- Windows Server 2022: build 10.0.20348.5870 or later
- Windows Server 2025 and Server Core: build 10.0.26100.33822 or later
- Patch: November 2026 security update. For Windows Server 2019 a third-party source lists KB5131085; other KB numbers are unknown.
Workaround
Unknown. No vendor-documented workaround was found.
- Interim step if patching is delayed (own recommendation, not from the vendor): restrict which hosts can reach NFS shares and review share permissions.
Exploitation
- Not known to be exploited in the wild.
- CISA SSVC: exploitation none, automatable no, technical impact partial.
- Rapid7 rates exploitation as Less Likely and lists it as not publicly disclosed.
- No public proof of concept found.
Our recommendation
- Install the November 2026 security update on all Windows Server systems listed above, starting with NFS file servers.
- Check whether the Server for NFS role is installed (Get-WindowsFeature or Server Manager).
- Until patched, limit NFS access to required hosts and review share permissions.
- Review accounts with local logon rights on affected servers.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Information disclosure – Windows Server for NFS
- 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, KB5131090, KB5131080, KB5131077
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide (CVE-2026-118140) msrc.microsoft.com
- CVE.org record CVE-2026-118140 www.cve.org
- Strix mirror CVE-2026-118140 www.strix.ai
- Senserva KB5131085 senserva.com
- Rapid7 November 2026 Patch Tuesday www.rapid7.com
- BleepingComputer November 2026 Patch Tuesday www.bleepingcomputer.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, 16:45.
Original description (NVD)
Improper access control in Windows Server for NFS allows an authorized attacker to disclose information 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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