A tampering vulnerability exists in Microsoft Windows when a man-in-the-middle attacker is able to successfully bypass the NTLM MIC (Message Integrity Check) protection. An attacker who successfully exploited this vulnerability could gain the ability to downgrade NTLM security features.
To exploit this vulnerability, the attacker would need to tamper with the NTLM exchange. The attacker could then modify flags of the NTLM packet without invalidating the signature.
The update addresses the vulnerability by hardening NTLM MIC protection on the server-side.

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact None

User Interaction Required

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact None

User Interaction None

Access Vector Network

Access Complexity Medium

Authentication None

Confidentiality Impact None

Integrity Impact Partial

Availability Impact None

This CVE is not in the KEV list.

The EPSS score is 0.89678.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Microsoft Windows 10 Version 1703 affected
Version Status Constraints
10.0.0 affected < publication
Microsoft Windows 10 Version 1803 affected
Version Status Constraints
10.0.0 affected < publication
Microsoft Windows Server, version 1803 (Server Core Installation) affected
Version Status Constraints
10.0.0 affected < publication
Microsoft Windows 10 Version 1809 affected
Version Status Constraints
10.0.17763.0 affected < publication
Microsoft Windows 10 Version 1809 affected
Version Status Constraints
10.0.0 affected < publication
Microsoft Windows Server 2019 affected
Version Status Constraints
10.0.17763.0 affected < publication
Microsoft Windows Server 2019 (Server Core installation) affected
Version Status Constraints
10.0.17763.0 affected < publication
Microsoft Windows 10 Version 1709 for 32-bit Systems affected
Version Status Constraints
10.0.0 affected < publication
Microsoft Windows 10 Version 1709 affected
Version Status Constraints
10.0.0 affected < publication
Microsoft Windows 10 Version 1903 for 32-bit Systems affected
Version Status Constraints
10.0.0 affected < publication
Microsoft Windows 10 Version 1903 for x64-based Systems affected
Version Status Constraints
10.0.0 affected < publication
Microsoft Windows 10 Version 1903 for ARM64-based Systems affected
Version Status Constraints
10.0.0 affected < publication
Microsoft Windows Server, version 1903 (Server Core installation) affected
Version Status Constraints
10.0.0 affected < publication
Microsoft Windows 10 Version 1507 affected
Version Status Constraints
10.0.10240.0 affected < publication
Microsoft Windows 10 Version 1607 affected
Version Status Constraints
10.0.14393.0 affected < publication
Microsoft Windows Server 2016 affected
Version Status Constraints
10.0.14393.0 affected < publication
Microsoft Windows Server 2016 (Server Core installation) affected
Version Status Constraints
10.0.14393.0 affected < publication
Microsoft Windows 7 affected
Version Status Constraints
6.1.0 affected < publication
Microsoft Windows 7 Service Pack 1 affected
Version Status Constraints
6.1.0 affected < publication
Microsoft Windows 8.1 affected
Version Status Constraints
6.3.0 affected < publication
Microsoft Windows Server 2008 Service Pack 2 affected
Version Status Constraints
6.0.6003.0 affected < publication
Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) affected
Version Status Constraints
6.0.6003.0 affected < publication
Microsoft Windows Server 2008 Service Pack 2 affected
Version Status Constraints
6.0.0 affected < publication
Microsoft Windows Server 2008 Service Pack 2 affected
Version Status Constraints
6.0.6003.0 affected < publication
Microsoft Windows Server 2008 R2 Systems Service Pack 1 affected
Version Status Constraints
6.1.0 affected < publication
Microsoft Windows Server 2008 R2 Service Pack 1 affected
Version Status Constraints
6.1.7601.0 affected < publication
Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) affected
Version Status Constraints
6.1.7601.0 affected < publication
Microsoft Windows Server 2012 affected
Version Status Constraints
6.2.9200.0 affected < publication
Microsoft Windows Server 2012 (Server Core installation) affected
Version Status Constraints
6.2.9200.0 affected < publication
Microsoft Windows Server 2012 R2 affected
Version Status Constraints
6.3.9600.0 affected < publication
Microsoft Windows Server 2012 R2 (Server Core installation) affected
Version Status Constraints
6.3.9600.0 affected < publication

Configuration 1 [-]

OR cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:1607:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:1703:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:1709:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:1803:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:1903:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:itanium:*
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:1803:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:1903:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*

No data.

No data.

Project Subscriptions

Vendors Products
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Windows 10 Subscribe
Windows 10 1507 Subscribe
Windows 10 1607 Subscribe
Windows 10 1809 Subscribe
Windows 7 Subscribe
Windows 8.1 Subscribe
Windows Rt 8.1 Subscribe
Windows Server 1803 Subscribe
Windows Server 1903 Subscribe
Windows Server 2008 Subscribe
Windows Server 2008 R2 Subscribe
Windows Server 2008 Sp2 Subscribe
Windows Server 2012 Subscribe
Windows Server 2012 R2 Subscribe
Windows Server 2016 Subscribe
Windows Server 2019 Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2019-1040 cve-icon cve-icon
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1040 cve-icon
History

Fri, 20 Feb 2026 21:00:00 +0000

Type Values Removed Values Added
First Time appeared Microsoft windows 10 1507
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows Server 1803
Microsoft windows Server 1903
Microsoft windows Server 2008 R2
Microsoft windows Server 2008 Sp2
Microsoft windows Server 2012 R2
CPEs cpe:2.3:o:microsoft:windows_10:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
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_7:*:sp1:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_7:*:sp1:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_8.1:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_server_1803:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_1903:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:*:sp2:*:*:*:*:itanium:*
cpe:2.3:o:microsoft:windows_server_2008_R2:*:*:*:*:*:*:itanium:*
cpe:2.3:o:microsoft:windows_server_2008_R2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2008_sp2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2008_sp2:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_server_2012:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
Vendors & Products Microsoft windows 10 1507
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows Server 1803
Microsoft windows Server 1903
Microsoft windows Server 2008 R2
Microsoft windows Server 2008 Sp2
Microsoft windows Server 2012 R2

Wed, 16 Jul 2025 13:45:00 +0000

Type Values Removed Values Added
Metrics epss

{'score': 0.86668}

 epss

{'score': 0.9061}

Tue, 20 May 2025 18:00:00 +0000

Type Values Removed Values Added
Description A tampering vulnerability exists in Microsoft Windows when a man-in-the-middle attacker is able to successfully bypass the NTLM MIC (Message Integrity Check) protection, aka 'Windows NTLM Tampering Vulnerability'. A tampering vulnerability exists in Microsoft Windows when a man-in-the-middle attacker is able to successfully bypass the NTLM MIC (Message Integrity Check) protection. An attacker who successfully exploited this vulnerability could gain the ability to downgrade NTLM security features. To exploit this vulnerability, the attacker would need to tamper with the NTLM exchange. The attacker could then modify flags of the NTLM packet without invalidating the signature. The update addresses the vulnerability by hardening NTLM MIC protection on the server-side.
Title Windows NTLM Tampering Vulnerability
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N/E:P/RL:O/RC:C'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2025-05-20T17:50:16.225Z

Reserved: 2018-11-26T00:00:00.000Z

Link: CVE-2019-1040

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2019-06-12T14:29:03.713

Modified: 2025-05-20T18:15:39.637

Link: CVE-2019-1040

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses