CVE-2019-1166: Microsoft Windows 10

Medium severity, CVSS 5.9. EPSS: 68.1% chance of exploitation in the next 30 days.

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'.

Affected products

• Microsoft Windows 10: affected versions not specified; version 1607 only; version 1703 only; version 1709 only; version 1803 only; version 1809 only; …
• Microsoft Windows 7: affected versions not specified
• Microsoft Windows 8.1: affected versions not specified
• Microsoft Windows Rt 8.1: affected versions not specified
• Microsoft Windows Server 2008: affected versions not specified; version r2 only
• Microsoft Windows Server 2012: affected versions not specified; version r2 only
• Microsoft Windows Server 2016: affected versions not specified; version 1803 only; version 1903 only
• Microsoft Windows Server 2019: affected versions not specified

Published 2019-10-10. Last modified 2026-06-17.