Windows Client for NFS: Out-of-bounds read causes information disclosure
Summary
The Windows Client for NFS component contains an out-of-bounds read (CWE-125). An unauthorized attacker on the network can read small portions of heap memory, which leads to information disclosure with no impact on integrity or availability. Exploitation requires user interaction (UI:R). Microsoft rates exploitation as less likely, and no public exploit code is known.
Affected
- Windows 10 Version 1607 (builds before 10.0.14393.9612)
- Windows 10 Version 1809 (builds before 10.0.17763.9376)
- Windows 10 Version 21H2 (builds before 10.0.19044.7807)
- Windows 10 Version 22H2 (builds before 10.0.19045.7807)
- Windows 11 Version 23H2 (builds before 10.0.22631.7652)
- Windows 11 Version 24H2 (builds before 10.0.26100.9711)
- Windows 11 Version 25H2 (builds before 10.0.26200.9711)
- Windows 11 Version 26H1 (builds before 10.0.28000.3231)
- Windows 11 Version 26H2 (builds before 10.0.26300.9711)
- Windows Server 2012 and 2012 R2 (builds before 6.2.9200.26434 and 6.3.9600.23470)
- Windows Server 2016 (builds before 10.0.14393.9612)
- Windows Server 2019, 2022 and 2025: fixed builds unconfirmed
Fixed in
- Microsoft security updates for the builds listed above. KB numbers are not confirmed in the sources; use the MSRC Security Update Guide.
- Windows Server 2025 build: sources conflict (10.0.26100.9711 vs. 10.0.26100.33650); verify on MSRC.
Workaround
- Unknown. No vendor workaround was found in the sources.
- Unofficial suggestion: disable or remove the Client for NFS feature where it is not needed, and restrict NFS traffic to known servers with firewall rules.
Exploitation
- Not publicly disclosed and not known to be exploited (MSRC).
- Exploit code maturity: Unproven; no public proof of concept found.
- Not in the CISA KEV catalog; CISA SSVC: exploitation none, not automatable.
- EPSS below 1% (about 0.009).
Our recommendation
- Apply the Microsoft security update for each affected Windows version as soon as possible. Prioritize hosts that mount NFS shares from untrusted or internet-reachable servers.
- Inventory systems with the Client for NFS feature enabled.
- Check the lifecycle status of Windows 10 1607 and Server 2016 on Microsoft's Lifecycle page. If out of support, plan an upgrade or Extended Security Updates.
- Verify the Windows Server 2025 fixed build on MSRC before relying on it.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Information disclosure – Windows Client 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)
- KB5126835, KB5126836, KB5126868, KB5126651, KB5126657, KB5126655
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide msrc.microsoft.com
- NVD data via Vulners vulners.com
- OpenCVE app.opencve.io
- Strix CNA data mirror www.strix.ai
- Microsoft partner cohort list 2026 cdn-dynmedia-1.microsoft.com
- EPSS data via Vulners vulners.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 5 Nov 2026, 11:25.
Original description (NVD)
Out-of-bounds read in Windows Client for NFS allows an unauthorized attacker to disclose information over a network.
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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