CVE-2021-31977
published 2021-06-08CVE-2021-31977: Windows Hyper-V Denial of Service Vulnerability Windows Hyper-V Denial of Service Vulnerability
high8.6CVSS 3.1
AVNACLPRNUINSCCNINAH
EPSS
3.18%
86.7th percentile
Windows Hyper-V Denial of Service Vulnerability
Windows Hyper-V Denial of Service Vulnerability
Affected
20 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | windows_10_version_1507 | >= 10.0.0 < 10.0.10240.18967 | 10.0.10240.18967 |
| microsoft | windows_10_version_1607 | >= 10.0.0 < 10.0.14393.4467 | 10.0.14393.4467 |
| microsoft | windows_10_version_1809 | >= 10.0.0 < 10.0.17763.1999 | 10.0.17763.1999 |
| microsoft | windows_10_version_1909 | >= 10.0.0 < 10.0.18363.1621 | 10.0.18363.1621 |
| microsoft | windows_10_version_2004 | >= 10.0.0 < 10.0.19041.1052 | 10.0.19041.1052 |
| microsoft | windows_10_version_21h1 | >= 10.0.0 < 10.0.19043.1052 | 10.0.19043.1052 |
| microsoft | windows_server_2016 | >= 10.0.0 < 10.0.14393.4467 | 10.0.14393.4467 |
| microsoft | windows_server_2019 | >= 10.0.0 < 10.0.17763.1999 | 10.0.17763.1999 |
| microsoft | windows_server_version_2004 | >= 10.0.0 < 10.0.19041.1052 | 10.0.19041.1052 |
| microsoft | windows_server_version_20h2 | >= 10.0.0 < 10.0.19042.1052 | 10.0.19042.1052 |
| msrc | windows_10_for_x64-based_systems | — | — |
| msrc | windows_10_version_1607_for_x64-based_systems | — | — |
| msrc | windows_10_version_1809_for_x64-based_systems | — | — |
| msrc | windows_10_version_1909_for_x64-based_systems | — | — |
| msrc | windows_10_version_2004_for_x64-based_systems | — | — |
| msrc | windows_10_version_21h1_for_x64-based_systems | — | — |
| msrc | windows_server_2016 | — | — |
| msrc | windows_server_2019 | — | — |
| msrc | windows_server_version_2004 | — | — |
| msrc | windows_server_version_20h2 | — | — |
CVSS provenance
nvdv3.18.6HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:N/I:N/A:P
cvelistv58.6HIGH
vendor_msrc8.6HIGH
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CVEList
Windows Hyper-V Denial of Service Vulnerability
cvelistv5·2021-06-08·CVSS 8.6
CVE-2021-31977 [HIGH] Windows Hyper-V Denial of Service Vulnerability
Windows Hyper-V Denial of Service Vulnerability
Windows Hyper-V Denial of Service Vulnerability
Microsoft
Windows Hyper-V Denial of Service Vulnerability
vendor_msrc·2021-06-08·CVSS 8.6
CVE-2021-31977 [HIGH] Windows Hyper-V Denial of Service Vulnerability
Windows Hyper-V Denial of Service Vulnerability
FAQ: How might an attacker attempt to exploit this vulnerability?
By sending a specially crafted message to the Hyper-V host virtualization stack, a guest VM could cause a reference count in the host virtualization stack to be leaked. In most circumstances, this would result in a memory leak on the Hyper-V host. If the leaked reference count value were to overflow, reference count hardening built-in to the Hyper-V virtualization stack would cause the host to bugcheck (crash) in a controlled manner, mitigating this issue against exploitation for code execution or privilege elevation.
Role: Windows Hyper-V: Role: Windows Hyper-V
Microsoft: Microsoft
Impact: Denial of Service
Exploit Status: Publicly Disclosed:No;Exploited:No;Latest Softwar
No detection rules found.
No public exploits indexed.
Qualys
Microsoft & Adobe Patch Tuesday (June 2021) – Microsoft 50 Vulnerabilities with 5 Critical, Adobe 21 Critical Vulnerabilities
blogs_qualys·2021-06-08·CVSS 5.2
CVE-2021-31985 [MEDIUM] Microsoft & Adobe Patch Tuesday (June 2021) – Microsoft 50 Vulnerabilities with 5 Critical, Adobe 21 Critical Vulnerabilities
## Microsoft Patch Tuesday – June 2021
Microsoft patched 50 CVEs in their June 2021 Patch Tuesday release, and five of them are rated as critical severity. Six have applicable exploits.
## Critical Microsoft Vulnerabilities Patched
CVE-2021-31985 – Microsoft Defender Remote Code Execution Vulnerability
Microsoft released patches addressing a critical RCE vulnerability in its Defender product (CVE-2021-31985). This CVE has a high likelihood of exploitability and is assigned a CVSSv3 base score of 7.8 by the vendor.
CVE-2021-31959 – Scripting Engine Memory Corruption Vulnerability
Microsoft released patches addressing a critical memory corruption vulnerability in the Chakra JScript scripting engine. This vulnerability impacts Windows RT, Windows 7, Windows 8, Windows 10, Windows Server
Crowdstrike
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Crowdstrike
June 2021 Patch Tuesday: Updates and Analysis
blogs_crowdstrike·CVSS 7.5
CVE-2026-20929 [HIGH] June 2021 Patch Tuesday: Updates and Analysis
STARDUST CHOLLIMA Likely Compromises Axios npm Package Apr 01, 2026
Falcon for IT Supports Windows Secure Boot Certificate Lifecycle Management Apr 01, 2026
Detecting CVE-2026-20929: Kerberos Authentication Relay via CNAME Abuse Mar 31, 2026
How Charlotte AI AgentWorks Fuels Security's Agentic Ecosystem Mar 25, 2026
STARDUST CHOLLIMA Likely Compromises Axios npm Package Apr 01, 2026
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Detecting CVE-2026-20929: Kerberos Authentication Relay via CNAME Abuse Mar 31, 2026
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2021-06-08
Published