Windows Hyper-V
CVE-2020-0661 — Windows Hyper-V Denial of Service Vulnerability
Executive Summary
A denial of service vulnerability exists when Microsoft Hyper-V on a host server fails to properly validate input from a privileged user on a guest operating system. To exploit the vulnerability, an attacker who already has a privileged account on a guest operating system, running as a virtual machine, could run a specially crafted application that causes a host machine to crash. To exploit the vulnerability, an attacker who already has a privileged account on a guest operating system, running as a virtual machine, could run a specially crafted application. The security update addresses the vulnerability by resolving a number of conditions where Hyper-V would fail to prevent a guest operating system from sending malicious requests.
Overview
6.8
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:P/RL:O/RC:C
ATTACK VECTOR
Adjacent_network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Changed
CONFIDENTIALITY
None
INTEGRITY
None
AVAILABILITY
High
EXPLOIT CODE MATURITY
Proof-of-Concept
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 6.1
EPSS Score
0.01632
probability of exploitation in the next 30 days
0.73156 percentile - updated 2026-06-21
View on FIRST.org
Affected Products
9 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Windows 10 Version 1607 for x64-based Systems | 4537764 (Security Update) |
Important | Denial of Service | Yes |
| Windows 10 Version 1809 for x64-based Systems | 4532691 (Security Update) |
Important | Denial of Service | Yes |
| Windows 10 Version 1909 for x64-based Systems | 4532693 (Security Update) |
Important | Denial of Service | Yes |
| Windows Server 2016 | 4537764 (Security Update) |
Important | Denial of Service | Yes |
| Windows Server 2016 (Server Core installation) | 4537764 (Security Update) |
Important | Denial of Service | Yes |
| Windows Server 2019 | 4532691 (Security Update) |
Important | Denial of Service | Yes |
| Windows Server 2019 (Server Core installation) | 4532691 (Security Update) |
Important | Denial of Service | Yes |
| Windows Server, version 1903 (Server Core installation) | 4532693 (Security Update) |
Important | Denial of Service | Yes |
| Windows Server, version 1909 (Server Core installation) | 4532693 (Security Update) |
Important | Denial of Service | Yes |
Patches
3 patches
| Article | Type | Restart |
|---|---|---|
4537764 |
Security Update | Yes |
4532691 |
Security Update | Yes |
4532693 |
Security Update | Yes |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
None
References
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