CVE-2019-1040Windows 10 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.
Published Jun 12, 2019 · Updated May 20, 2025
Key Facts
Patch immediately- CVE-2019-1040 is a medium-severity vulnerability (CVSS 5.3 v3.1) affecting Windows 10 (Microsoft), Windows 7 (Microsoft), Windows 8.1 (Microsoft) and 22 more products.
- It is exploited in the wild, listed in Industry KEV feed since Oct 20, 2020. No public exploit code is known.
- EPSS estimates a 48% probability of exploitation in the next 30 days.
- Fixed versions are available, including Windows 10 Version 1507 publication, Windows 10 Version 1607 publication, Windows 10 Version 1703 publication.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Scores
CVSS v3.1
5.3
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
EPSS (30-day exploit likelihood)
48%
Higher than 98.8% of all scored CVEs
Exploit maturity
Exploited (KEV)
ATLAS score
45/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Oct 20, 2020
496 days after publication
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Exploited (KEV)
Public exploit code
0
Proof-of-concept links
In-the-wild evidence
1
Reports of active use
Advisories And Exploit References
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. 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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Oct 20, 2020 | n/a | Not reported |
Affected Products
48 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Windows 10Microsoft | 1607, 1703, 1709, 1803, 1809, 1903 | n/a |
| Windows 7Microsoft | >= 6.1.0 | publication |
| Windows 8.1Microsoft | >= 6.3.0 | publication |
| Windows Rt 8.1Microsoft | See advisory | n/a |
| Windows Server 2008Microsoft | r2-sp1 | n/a |
Patched Releases
Windows 10 Version 1507
publication
Windows 10 Version 1607
publication
Windows 10 Version 1703
publication
Windows 10 Version 1709
publication
Windows 10 Version 1709 for 32-bit Systems
publication
Windows 10 Version 1803
publication
Windows 10 Version 1809
publication
Windows 10 Version 1903 for 32-bit Systems
publication
Windows 10 Version 1903 for ARM64-based Systems
publication
Windows 10 Version 1903 for x64-based Systems
publication
Windows 7
publication
Windows 7 Service Pack 1
publication
Windows 8.1
publication
Windows Server 2008 Service Pack 2
publication
Windows Server 2008 R2 Service Pack 1
publication
Windows Server 2008 R2 Service Pack 1 (Server Core installation)
publication
Windows Server 2008 R2 Systems Service Pack 1
publication
Windows Server 2008 Service Pack 2 (Server Core installation)
publication
Windows Server 2012
publication
Windows Server 2012 (Server Core installation)
publication
Windows Server 2012 R2
publication
Windows Server 2012 R2 (Server Core installation)
publication
Windows Server 2016
publication
Windows Server 2016 (Server Core installation)
publication
Windows Server 2019
publication
Timeline
Publicly disclosed
Jun 12, 2019
Added to Industry KEV feed
Oct 20, 2020
Last updated
May 20, 2025
References
FAQ
Common Questions.
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.
Affected: Windows 10 (Microsoft) versions 1607, 1703, 1709, 1803, 1809, 1903; Windows 7 (Microsoft) versions >= 6.1.0; Windows 8.1 (Microsoft) versions >= 6.3.0, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Oct 20, 2020.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Windows 10 Version 1507 publication, Windows 10 Version 1607 publication, Windows 10 Version 1703 publication.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Is CVE-2019-1040 On Your Attack Surface?
Brandefense matches it against the products discovered on your perimeter and opens a finding the day a CVE like this is listed.
Request A Demo