Description
Heap-based buffer overflow in Windows Network File System allows an authorized attacker to elevate privileges over a network.
Published: 2026-07-14
Score: 8.8 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

This vulnerability is a heap‑based buffer overflow in the Windows Network File System (NFS) service. The bug arises when the service fails to verify data received from a client, causing an uncontrolled write that can lead to arbitrary code execution or privilege escalation. The flaw is classified under buffer overflow (CWE-122) and arithmetic overflow (CWE-190) weaknesses.

Affected Systems

Affected systems include Microsoft Windows 10 (versions 1607, 1809, 21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server releases 2012, 2012 R2, 2016, 2019, 2022, and 2025. All installations that enable the Windows NFS Server component, whether full or Server Core, are vulnerable.

Risk and Exploitability

The CVSS score of 8.8 indicates a high‑severity flaw, while the EPSS score of less than 1 % suggests that active exploitation is currently uncommon or not yet widespread. The vulnerability is not listed in the CISA KEV catalog, providing no evidence of known active attacks. Because the flaw requires an attacker to be authorized on the network and able to reach the NFS service, it is a network‑based privilege‑elevation vulnerability that could be abused by authenticated users with sufficient access rights.

Generated by OpenCVE AI on August 1, 2026 at 09:28 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the latest Microsoft security update that addresses CVE‑2026‑56194.
  • If the NFS service is not required for business operations, disable or uninstall it to eliminate the attack surface.
  • When the NFS server must remain operational, limit client connections to trusted internal hosts by configuring firewall rules or network segmentation.
  • Ensure that file‑sharing permissions and NFS ACLs enforce least privilege for all shared resources.

Generated by OpenCVE AI on August 1, 2026 at 09:28 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Tue, 14 Jul 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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

Tue, 14 Jul 2026 17:45:00 +0000

Type Values Removed Values Added
Description Heap-based buffer overflow in Windows Network File System allows an authorized attacker to elevate privileges over a network.
Title Windows NFS Server 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-190
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': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C'}

Subscriptions

Microsoft Windows 10 1607 Windows 10 1809 Windows 10 21h2 Windows 10 22h2 Windows 11 24h2 Windows 11 25h2 Windows 11 26h1 Windows Server 2012 Windows Server 2012 R2 Windows Server 2016 Windows Server 2019 Windows Server 2022 Windows Server 2025
cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2026-08-03T22:57:48.385Z

Reserved: 2026-06-19T13:54:04.006Z

Link: CVE-2026-56194

cve-icon Vulnrichment

Updated: 2026-07-14T18:48:17.252Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-01T09:30:03Z

Weaknesses
  • CWE-122

    Heap-based Buffer Overflow

  • CWE-190

    Integer Overflow or Wraparound