CVE-2020-1243
CVE-2020-1243 is a high-severity vulnerability in Microsoft Windows 10 with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.
Key facts
- Severity: High (CVSS 3.x base score 7.8)
- CVSS v2: 4.6
- EPSS exploit prediction: 1% (55th percentile)
- Actively exploited: Not listed in CISA KEV
- Affected product: Microsoft Windows 10
- Published:
- Last modified:
Description
<p>A denial of service vulnerability exists when Microsoft Hyper-V on a host server fails to properly validate specific malicious data from a user on a guest operating system.</p> <p>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.</p> <p>The security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to handle these requests.</p>
Frequently asked questions
- What is CVE-2020-1243?
- <p>A denial of service vulnerability exists when Microsoft Hyper-V on a host server fails to properly validate specific malicious data from a user on a guest operating system.</p> <p>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.</p> <p>The security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to handle these requests.</p>
- How severe is CVE-2020-1243?
- CVE-2020-1243 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2020-1243 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-1243?
- CVE-2020-1243 primarily affects Microsoft Windows 10. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2020-1243?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2020-1243 published?
- CVE-2020-1243 was published on 2020-10-16 and last updated on 2026-06-17.
References
Affected products (11)
- cpe:2.3:o:microsoft:windows_10:1607:*:*:*:*:*:x64:*
- cpe:2.3:o:microsoft:windows_10:1709:*:*:*:*:*:x64:*
- cpe:2.3:o:microsoft:windows_10:1803:*:*:*:*:*:x64:*
- cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:x64:*
- cpe:2.3:o:microsoft:windows_10:1903:*:*:*:*:*:x64:*
- cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:x64:*
- cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2016:1903:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2016:1909:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:*
- cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*
More vulnerabilities in Microsoft Windows 10
- CVE-2020-1467 — Critical (CVSS 10.0): An elevation of privilege vulnerability exists when Windows improperly handles hard links. An attacker who successfully…
- CVE-2021-26424 — Critical (CVSS 9.9): Windows TCP/IP Remote Code Execution Vulnerability
- CVE-2021-28476 — Critical (CVSS 9.9): Windows Hyper-V Remote Code Execution Vulnerability
- CVE-2021-26867 — Critical (CVSS 9.9): Windows Hyper-V Remote Code Execution Vulnerability
- CVE-2020-1112 — Critical (CVSS 9.9): An elevation of privilege vulnerability exists when the Windows Background Intelligent Transfer Service (BITS) IIS…
- CVE-2019-1384 — Critical (CVSS 9.9): A security feature bypass vulnerability exists where a NETLOGON message is able to obtain the session key and sign…