{"id":"CVE-2020-1243","aliases":["EUVD-2020-12122","GHSA-xmww-w83v-qcv7"],"status":"published","title":"Windows Hyper-V Denial of Service Vulnerability","description":"\u003cp\u003eA 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.\u003c/p\u003e\n\u003cp\u003eTo 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.\u003c/p\u003e\n\u003cp\u003eThe security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to handle these requests.\u003c/p\u003e","severity":{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.009,"percentile":0.59974,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"published":"2020-10-16T22:18:14Z","modified":"2026-06-17T03:00:53Z","products":[{"vendor":"microsoft","product":"windows 10 version 1607"},{"vendor":"microsoft","product":"windows 10 version 1709"},{"vendor":"microsoft","product":"windows 10 version 1803"},{"vendor":"microsoft","product":"windows 10 version 1809"},{"vendor":"microsoft","product":"windows 10 version 1903 for x64-based systems"},{"vendor":"microsoft","product":"windows 10 version 1909"},{"vendor":"microsoft","product":"windows 10 version 2004"},{"vendor":"microsoft","product":"windows server 2016"},{"vendor":"microsoft","product":"windows server 2016 (server core installation)"},{"vendor":"microsoft","product":"windows server 2019"},{"vendor":"microsoft","product":"windows server 2019 (server core installation)"},{"vendor":"microsoft","product":"windows server version 2004"},{"vendor":"microsoft","product":"windows server, version 1903 (server core installation)"},{"vendor":"microsoft","product":"windows server, version 1909 (server core installation)"},{"vendor":"microsoft","product":"windows_10"},{"vendor":"microsoft","product":"windows_server_2016"},{"vendor":"microsoft","product":"windows_server_2019"}],"references":[{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1243","tags":["x_refsource_MISC","x_transferred","Patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-1243"},{"url":"https://github.com/advisories/GHSA-xmww-w83v-qcv7"}],"sources":{"cve":[{"id":"CVE-2020-1243","title":"Windows Hyper-V Denial of Service Vulnerability","description":"\u003cp\u003eA 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.\u003c/p\u003e\n\u003cp\u003eTo 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.\u003c/p\u003e\n\u003cp\u003eThe security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to handle these requests.\u003c/p\u003e","status":"published","published":"2020-10-16T22:18:14Z","modified":"2024-08-04T06:31:59.966Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C","level":"high","assessor":"cna"}],"updated_at":"2026-11-02T14:35:56.638833Z"}],"euvd":[{"id":"EUVD-2020-12122","description":"\u003cp\u003eA 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.\u003c/p\u003e\n\u003cp\u003eTo 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.\u003c/p\u003e\n\u003cp\u003eThe security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to handle these requests.\u003c/p\u003e","status":"published","published":"2020-10-16T22:18:14Z","modified":"2024-08-04T06:31:59Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C","level":"high"}],"updated_at":"2026-11-03T03:08:14.784772Z"}],"ghsa":[{"id":"GHSA-xmww-w83v-qcv7","title":"A denial of service vulnerability exists when Microsoft Hyper-V on a host server fails to...","description":"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.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 the conditions where Hyper-V would fail to handle these requests., aka 'Windows Hyper-V Denial of Service Vulnerability'.","status":"published","published":"2022-05-24T17:30:50Z","modified":"2024-01-09T05:05:03Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T14:55:21.919096Z"}],"nvd":[{"id":"CVE-2020-1243","description":"\u003cp\u003eA 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.\u003c/p\u003e\n\u003cp\u003eTo 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.\u003c/p\u003e\n\u003cp\u003eThe security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to handle these requests.\u003c/p\u003e","status":"published","published":"2020-10-16T23:15:17.68Z","modified":"2026-06-17T03:00:53.447Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"},{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"},{"version":"2.0","score":4.6,"vector":"AV:L/AC:L/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:06:19.351389Z"}]}}