{"id":"CVE-2020-1118","title":"A denial of service vulnerability exists in the Windows implementation of Transport Layer Security (TLS) when it improperly handles certain key exchanges","summary":"A denial of service vulnerability exists in the Windows implementation of Transport Layer Security (TLS) when it improperly handles certain key exchanges. An attacker who successfully exploited the vulnerability could cause a target syst…","severity":"high","cvss":8.6,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","vendor":"microsoft","product":"windows_10","affected":["windows_10 = 1709","windows_10 = 1803","windows_10 = 1809","windows_10 = 1903","windows_10 = 1909","windows_server_2019","windows_server_2019 = 1903","windows_server_2019 = 1909"],"published":"2020-05-21","updated":"2026-08-19","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2020-1118","references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1118","label":"secure@microsoft.com"},{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1118","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.14681,"epssPercentile":0.96509,"ingestedAt":"2026-08-19T17:42:38.580Z","slug":"CVE-2020-1118","body":"## Overview\n\nA denial of service vulnerability exists in the Windows implementation of Transport Layer Security (TLS) when it improperly handles certain key exchanges. An attacker who successfully exploited the vulnerability could cause a target system to stop responding.\nTo exploit this vulnerability, a remote unauthenticated attacker could send a specially crafted request to a target system utilizing TLS 1.2 or lower, triggering the system to automatically reboot.\nThe update addresses the vulnerability by changing the way TLS key exchange messages are validated.\n\n## Affected\n\n- `windows_10 = 1709`\n- `windows_10 = 1803`\n- `windows_10 = 1809`\n- `windows_10 = 1903`\n- `windows_10 = 1909`\n- `windows_server_2019`\n- `windows_server_2019 = 1903`\n- `windows_server_2019 = 1909`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":50,"depthScoreParts":{"impact":47.3,"likelihood":2.9,"exploitation":0,"ransomware":0},"changes":[]}