CVE-2019-1040
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2019-1040- CVSS 3.1
- 5.3 Medium
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 - Updated
- 2026-11-02
EUVDEUVD-2019-9625
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.
- Record
EUVD-2019-9625- CVSS 3.1
- 5.3 Medium
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-8vpr-83m7-3f7q
A tampering vulnerability exists in Microsoft Windows when a man-in-the-middle attacker is able...
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'.
- Record
GHSA-8vpr-83m7-3f7q- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
NVD
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.
- Record
CVE-2019-1040- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N - CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Updated
- 2026-11-02
Affected products
- microsoft windows 10 version 1507
- microsoft windows 10 version 1607
- microsoft windows 10 version 1703
- microsoft windows 10 version 1709
- microsoft windows 10 version 1709 for 32-bit systems
- microsoft windows 10 version 1803
- microsoft windows 10 version 1809
- microsoft windows 10 version 1903 for 32-bit systems
- microsoft windows 10 version 1903 for arm64-based systems
- microsoft windows 10 version 1903 for x64-based systems
- microsoft windows 7
- microsoft windows 7 service pack 1
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- microsoft windows 8.1
- microsoft windows server 2008 service pack 2
- microsoft windows server 2008 r2 service pack 1
- microsoft windows server 2008 r2 service pack 1 (server core installation)
- microsoft windows server 2008 r2 systems service pack 1
- microsoft windows server 2008 service pack 2
- microsoft windows server 2008 service pack 2 (server core installation)
- microsoft windows server 2012
- microsoft windows server 2012 (server core installation)
- microsoft windows server 2012 r2
- microsoft windows server 2012 r2 (server core installation)
- microsoft windows server 2016
- microsoft windows server 2016 (server core installation)
- microsoft windows server 2019
- microsoft windows server 2019 (server core installation)
- microsoft windows server, version 1803 (server core installation)
- microsoft windows server, version 1903 (server core installation)
- microsoft windows 10
- microsoft windows rt 8.1
- microsoft windows server 2008
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | JonyFilc/PrintSpoofer-ReflectiveDLL | 2025-12-06 |
| PoC in GitHub | QAX-A-Team/dcpwn | 2021-01-01 |
| PoC in GitHub | Ridter/CVE-2019-1040 | 2019-06-14 |
| PoC in GitHub | Ridter/CVE-2019-1040-dcpwn | 2019-06-18 |
| PoC in GitHub | fox-it/cve-2019-1040-scanner | 2019-06-24 |
| PoC in GitHub | lazaars/UltraRealy_with_CVE-2019-1040 | 2019-06-19 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2019-1040 is a medium vulnerability (CVSS 5.3) in Microsoft Windows 10 Version 1507, published June 12, 2019. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 48.0%, the 98th percentile. No source names a fixed version.