Junglewise Threat Intelligence

CVE-2026-56649: Microsoft Windows Network File System race condition remote code execution

CVE-2026-56649 · Severity: medium · CVSS 5.9 · Published 2026-07-14

Technologies: Microsoft Windows Server 2012, Microsoft Windows 10, Microsoft Windows 11. Vendors: Microsoft.

Executive brief

A security vulnerability exists in the Windows Network File System (NFS), a service used to share files between different computers over a network. An unauthorized attacker could exploit this flaw to remotely execute malicious code on a target server or workstation. This could lead to a complete system takeover, unauthorized data access, or significant disruption of business operations.

Technical details

This vulnerability is characterized as a race condition (CWE-362) and a use-after-free (CWE-416) within the Windows Network File System (NFS) component. The flaw occurs due to improper synchronization during concurrent execution when accessing shared resources. An unauthenticated attacker can exploit this over the network, though the attack complexity is rated as high, likely requiring specific timing or environmental conditions to trigger the race condition. Successful exploitation could allow for remote code execution (RCE). Microsoft has released security updates to address this issue across various Windows and Windows Server versions.

Affected products

  • Microsoft Windows 10 1607, 1809, 21H2, 22H2
  • Microsoft Windows 11 24H2, 25H2, 26H1
  • Microsoft Windows Server 2012 All versions

Timeline

  • 2026-07-14: advisory: Initial disclosure by Microsoft and NVD publication.

References

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