CVE-2019-1019 — Microsoft Windows Security Feature Bypass Vulnerability

Executive Summary

A security feature bypass vulnerability exists where a NETLOGON message is able to obtain the session key and sign messages. To exploit this vulnerability, an attacker could send a specially crafted authentication request. An attacker who successfully exploited this vulnerability could access another machine using the original user privileges. The issue has been addressed by changing how NTLM validates network authentication messages.

Overview

8.5

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Security Feature Bypass

Released Jun 11 2019

Last Updated Jun 11 2019

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.13844 — 0.96043 percentile

CVSS Vector

ATTACK VECTOR

Network

ATTACK COMPLEXITY

High

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Changed

Temporal Score: 7.6

EPSS Score

0.13844

probability of exploitation in the next 30 days

0.96043 percentile - updated 2026-06-20

View on FIRST.org

Affected Products

41 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 for 32-bit Systems	`4503291 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 for x64-based Systems	`4503291 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1607 for 32-bit Systems	`4503267 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1607 for x64-based Systems	`4503267 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1703 for 32-bit Systems	`4503279 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1703 for x64-based Systems	`4503279 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1709 for 32-bit Systems	`4503284 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1709 for ARM64-based Systems	`4503284 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1709 for x64-based Systems	`4503284 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1803 for 32-bit Systems	`4503286 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1803 for ARM64-based Systems	`4503286 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1803 for x64-based Systems	`4503286 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for 32-bit Systems	`4503327 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for ARM64-based Systems	`4503327 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for x64-based Systems	`4503327 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1903 for 32-bit Systems	`4503293 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1903 for ARM64-based Systems	`4503293 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1903 for x64-based Systems	`4503293 (Security Update)`	Important	Security Feature Bypass	No
Windows 7 for 32-bit Systems Service Pack 1	`4503292 (Monthly Rollup) 4503269 (Security Only)`	Important	Security Feature Bypass	Yes
Windows 7 for x64-based Systems Service Pack 1	`4503292 (Monthly Rollup) 4503269 (Security Only)`	Important	Security Feature Bypass	Yes
Windows 8.1 for 32-bit systems	`4503276 (Monthly Rollup) 4503290 (Security Only)`	Important	Security Feature Bypass	Yes
Windows 8.1 for x64-based systems	`4503276 (Monthly Rollup) 4503290 (Security Only)`	Important	Security Feature Bypass	Yes
Windows RT 8.1	`4503276 (Monthly Rollup)`	Important	Security Feature Bypass	Yes
Windows Server 2008 for 32-bit Systems Service Pack 2	`4503273 (Monthly Rollup) 4503287 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)	`4503273 (Monthly Rollup) 4503287 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2008 for Itanium-Based Systems Service Pack 2	`4503273 (Monthly Rollup) 4503287 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2008 for x64-based Systems Service Pack 2	`4503273 (Monthly Rollup) 4503287 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)	`4503273 (Monthly Rollup) 4503287 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1	`4503292 (Monthly Rollup) 4503269 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2008 R2 for x64-based Systems Service Pack 1	`4503292 (Monthly Rollup) 4503269 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)	`4503292 (Monthly Rollup) 4503269 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2012	`4503285 (Monthly Rollup) 4503263 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2012 (Server Core installation)	`4503285 (Monthly Rollup) 4503263 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2012 R2	`4503276 (Monthly Rollup) 4503290 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2012 R2 (Server Core installation)	`4503276 (Monthly Rollup) 4503290 (Security Only)`	Important	Security Feature Bypass	Yes
Windows Server 2016	`4503267 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2016 (Server Core installation)	`4503267 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2019	`4503327 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2019 (Server Core installation)	`4503327 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server, version 1803 (Server Core Installation)	`4503286 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server, version 1903 (Server Core installation)	`4503293 (Security Update)`	Important	Security Feature Bypass	No

Patches

12 patches

Article	Type	Restart
`4503291`	Security Update	Yes
`4503267`	Security Update	Yes
`4503279`	Security Update	Yes
`4503284`	Security Update	Yes
`4503286`	Security Update	Yes
`4503327`	Security Update	Yes
`4503293`	Security Update	Yes
`4503292 (Monthly Rollup) 4503269`	Monthly Rollup	Yes
`4503276 (Monthly Rollup) 4503290`	Monthly Rollup	Yes
`4503276`	Monthly Rollup	Yes
`4503273 (Monthly Rollup) 4503287`	Monthly Rollup	Yes
`4503285 (Monthly Rollup) 4503263`	Monthly Rollup	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

Preempt, Sergei Glazunov of Google Project Zero

References

MSRC Advisory MITRE NVD