Microsoft Windows Transport Layer Security Denial of Service Vulnerability

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Summary

CVECVE-2020-1118
StatePUBLISHED
Assignermicrosoft
Source PriorityCVE Program / NVD first with legacy fallback
Published2020-05-21 23:15:15 UTC
Updated2026-08-19 17:17:20 UTC
DescriptionA 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.173520000 probability, percentile 0.968640000 (date 2026-08-19)

Problem Types: NVD-CWE-Other | Denial of Service

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1[email protected]Primary8.6HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
3.1CNACVSS8.6HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:P/RL:O/RC:C
2.0[email protected]Primary7.8AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v2.0 Breakdown

Access Vector
Network
Access Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete

AV:N/AC:L/Au:N/C:N/I:N/A:C

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Microsoft Windows 10 1709 All All All
Operating System Microsoft Windows 10 1803 All All All
Operating System Microsoft Windows 10 1809 All All All
Operating System Microsoft Windows 10 1903 All All All
Operating System Microsoft Windows 10 1909 All All All
Operating System Microsoft Windows Server 2019 - All All All
Operating System Microsoft Windows Server 2019 1903 All All All
Operating System Microsoft Windows Server 2019 1909 All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Microsoft Windows 10 Version 1709 affected 10.0.0 publication custom ARM64-based Systems, x64-based Systems
CNA Microsoft Windows 10 Version 1709 For 32-bit Systems affected 10.0.0 publication custom 32-bit Systems
CNA Microsoft Windows 10 Version 1803 affected 10.0.0 publication custom 32-bit Systems, ARM64-based Systems, x64-based Systems
CNA Microsoft Windows 10 Version 1809 affected 10.0.17763.0 publication custom 32-bit Systems, x64-based Systems
CNA Microsoft Windows 10 Version 1809 affected 10.0.0 publication custom ARM64-based Systems
CNA Microsoft Windows 10 Version 1903 For 32-bit Systems affected 10.0.0 publication custom Not specified
CNA Microsoft Windows 10 Version 1903 For ARM64-based Systems affected 10.0.0 publication custom Not specified
CNA Microsoft Windows 10 Version 1903 For X64-based Systems affected 10.0.0 publication custom Not specified
CNA Microsoft Windows 10 Version 1909 affected 10.0.0 publication custom 32-bit Systems, ARM64-based Systems, x64-based Systems
CNA Microsoft Windows Server 2019 affected 10.0.17763.0 publication custom x64-based Systems
CNA Microsoft Windows Server 2019 Server Core Installation affected 10.0.17763.0 publication custom x64-based Systems
CNA Microsoft Windows Server Version 1803 Server Core Installation affected 10.0.0 publication custom x64-based Systems
CNA Microsoft Windows Server Version 1903 Server Core Installation affected 10.0.0 publication custom x64-based Systems
CNA Microsoft Windows Server Version 1909 Server Core Installation affected 10.0.0 publication custom x64-based Systems

References

ReferenceSourceLinkTags
msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1118 [email protected] msrc.microsoft.com
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1118 af854a3a-2127-422b-91ae-364da2661108 portal.msrc.microsoft.com Patch, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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