CVE-2019-1040
Windows NTLM Tampering Vulnerability
MEDIUM 5.3EPSS 48.0%
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.
- Affected
- Microsoft · Windows 10 Version 1703 · Windows 10 Version 1803 · Windows Server, version 1803 (Server Core Installation) · Windows 10 Version 1809 · Windows Server 2019 · Windows Server 2019 (Server Core installation)
- CVSS v3.1 MICROSOFT
- 5.3 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N - CVSS v3.0 NVD
- 5.9 MEDIUM
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS v2.0 NVD
- 4.3 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:N - EPSS
- 48.04% chance of exploitation in the next 30 days, 99th percentile
- Published
- 2019-06-12
- Updated
- 2025-05-20
Proof-of-concept exploits (4)
- Ridter/CVE-2019-1040249★ · 2021-06-18
- Ridter/CVE-2019-1040-dcpwn33★ · 2021-06-18
- lazaars/UltraRealy_with_CVE-2019-104019★ · 2019-06-19
- JonyFilc/PrintSpoofer-ReflectiveDLL2★ · 2026-08-15