CVE-2025-49751: Windows Hyper-V Denial of Service Vulnerability

Overview

Severity
Medium (CVSS 6.8)
CVSS Vector
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C
Category
Denial of Service
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2025-Aug
Released
2025-08-12
EPSS Score
0.19% (percentile: 40.5%)

Description

Missing synchronization in Windows Hyper-V allows an authorized attacker to deny service over an adjacent network.

FAQ

According to the CVSS metric, a successful exploitation could lead to a scope change (S:C). What does this mean for this vulnerability? In this case, a successful attack could be performed from a low privilege Hyper-V guest. The attacker could traverse the guest's security boundary to cause denial of service on the Hyper-V host environment. According to the CVSS metric, the Hyper-V attack vector is adjacent (AV:A). What does that mean for this vulnerability? Where the attack vector metric is Adjacent (A), this represents virtual machines connected via a Hyper-V Network Virtualization (HNV) logical network. This configuration forms an isolation boundary where the virtual machines within the virtual network can only communicate with each other. In this attack vector, the vulnerable component is bound to the network stack, but the attack is limited to systems configured to use the HNV network.

Affected Products (19)

Windows

  • Windows 10 Version 1809 for x64-based Systems
  • Windows Server 2019
  • Windows Server 2019 (Server Core installation)
  • Windows Server 2022
  • Windows Server 2022 (Server Core installation)
  • Windows 10 Version 21H2 for x64-based Systems
  • Windows Server 2025 (Server Core installation)
  • Windows 11 Version 23H2 for ARM64-based Systems
  • Windows 11 Version 23H2 for x64-based Systems
  • Windows Server 2022, 23H2 Edition (Server Core installation)
  • Windows 11 Version 24H2 for ARM64-based Systems
  • Windows 11 Version 24H2 for x64-based Systems
  • Windows Server 2025
  • Windows 10 Version 1607 for x64-based Systems
  • Windows Server 2016
  • Windows Server 2016 (Server Core installation)

ESU

  • Windows 11 Version 22H2 for ARM64-based Systems
  • Windows 11 Version 22H2 for x64-based Systems
  • Windows 10 Version 22H2 for x64-based Systems

Security Updates (9)

Acknowledgments

<a href="https://twitter.com/rthhh17">HongZhenhao</a> with <a href="https://twitter.com/tiangonglab">TianGong Team of Legendsec at Qi&#39;anxin Group</a>

Revision History

  • 2025-08-12: Information published.