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 system to stop responding.
To 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.
The update addresses the vulnerability by changing the way TLS key exchange messages are validated.

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History

Wed, 19 Aug 2026 16:45:00 +0000

Type Values Removed Values Added
Description A denial of service vulnerability exists in the Windows implementation of Transport Layer Security (TLS) when it improperly handles certain key exchanges, aka 'Microsoft Windows Transport Layer Security Denial of Service Vulnerability'. 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 system to stop responding. To 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. The update addresses the vulnerability by changing the way TLS key exchange messages are validated.
Title Microsoft Windows Transport Layer Security Denial of Service Vulnerability
First Time appeared Microsoft windows 10 1809
Microsoft windows 10 1909
Microsoft windows Server 1803
Microsoft windows Server 1903
Microsoft windows Server 1909
CPEs cpe:2.3:o:microsoft:windows_10:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1909:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_server_1803:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_1903:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_1909:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
Vendors & Products Microsoft windows 10 1809
Microsoft windows 10 1909
Microsoft windows Server 1803
Microsoft windows Server 1903
Microsoft windows Server 1909
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:P/RL:O/RC:C'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2026-08-19T16:33:39.283Z

Reserved: 2019-11-04T00:00:00.000Z

Link: CVE-2020-1118

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2020-05-21T23:15:15.460

Modified: 2026-08-19T17:17:20.220

Link: CVE-2020-1118

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses