CVE-2026-56650

Windows Network File System Elevation of Privilege Vulnerability

Published Jul 14, 2026 CVSS 3.1 · 7.8 High EPSS < 1% KEV · Not listed
Description
Heap-based buffer overflow in Windows Network File System allows an authorized attacker to elevate privileges locally.

Analysis

AI-generated

Technical impact

A heap-based buffer overflow exists in the Windows Network File System (NFS) component. An attacker who can already authenticate to the system and access the NFS service can exercise the overflow to gain code execution, thereby elevating their privileges to the system local administrator level. The weakness corresponds to CWE-122 and involves a data–value overflow described by CWE-197. The impact is the loss of integrity and confidentiality for all files and processes under the compromised account, and potentially availability issues if the attacker disrupts the NFS service.

Affected Systems

Microsoft Windows operating systems from Windows 10 version 1607 through Windows 11 version 26H1 and Windows Server family from 2012 to 2025, including both standard and server-core installations, are affected.

Risk and Exploitability

The CVSS score of 7.8 indicates a high severity vulnerability. The EPSS score, less than 1 %, shows a very low likelihood of exploitation in the wild, and the issue is not currently listed in the CISA KEV catalog. The attack vector is local and requires the attacker to be authenticated on the target machine with access to the NFS service. An exploit would typically involve crafting a malicious NFS request that triggers the overflow, though no public exploit has been disclosed. The overall risk is moderate, but because the vulnerability permits elevation to local administrator rights, it should be addressed promptly.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the Microsoft update that contains the fix for CVE-2026-56650, as listed in the Microsoft Security Update Guide
  • If the NFS client or server is not required for business operations, disable or uninstall the NFS component to eliminate the attack surface
  • Restrict file share permissions and use the principle of least privilege so that only authorized users can access the network file system

Generated by OpenCVE AI on July 31, 2026 at 06:23 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012 (server Core Installation)
Microsoft windows Server 2012 R2
Microsoft windows Server 2012 R2 (server Core Installation)
Microsoft windows Server 2016 (server Core Installation)
Microsoft windows Server 2019 (server Core Installation)
Microsoft windows Server 2025 (server Core Installation)
Vendors & Products Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012 (server Core Installation)
Microsoft windows Server 2012 R2
Microsoft windows Server 2012 R2 (server Core Installation)
Microsoft windows Server 2016 (server Core Installation)
Microsoft windows Server 2019 (server Core Installation)
Microsoft windows Server 2025 (server Core Installation)
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Heap-based buffer overflow in Windows Network File System allows an authorized attacker to elevate privileges locally.
Title Windows Network File System Elevation of Privilege Vulnerability
First Time appeared Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Weaknesses CWE-122
CWE-197
CPEs cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21H2:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_22H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_24H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26H1:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
References
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C'}