Windows NTLM
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
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
High
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Changed
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Proof-of-Concept
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.6
EPSS Score
0.13598
probability of exploitation in the next 30 days
0.96065 percentile - updated 2026-07-25
View on FIRST.org
Affected Products
25 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 4499164 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows 7 for x64-based Systems Service Pack 1 4503292 (Monthly Rollup) 4503269 (Security Only) Important Security Feature Bypass 4499164 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows 8.1 for 32-bit systems 4503276 (Monthly Rollup) 4503290 (Security Only) Important Security Feature Bypass 4499151 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows 8.1 for x64-based systems 4503276 (Monthly Rollup) 4503290 (Security Only) Important Security Feature Bypass 4499151 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None 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 4499149 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) 4503273 (Monthly Rollup) 4503287 (Security Only) Important Security Feature Bypass 4499149 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2008 for Itanium-Based Systems Service Pack 2 4503273 (Monthly Rollup) 4503287 (Security Only) Important Security Feature Bypass 4499149 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2008 for x64-based Systems Service Pack 2 4503273 (Monthly Rollup) 4503287 (Security Only) Important Security Feature Bypass 4499149 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 4503273 (Monthly Rollup) 4503287 (Security Only) Important Security Feature Bypass 4499149 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1 4503292 (Monthly Rollup) 4503269 (Security Only) Important Security Feature Bypass 4499164 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2008 R2 for x64-based Systems Service Pack 1 4503292 (Monthly Rollup) 4503269 (Security Only) Important Security Feature Bypass 4499164 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 4503292 (Monthly Rollup) 4503269 (Security Only) Important Security Feature Bypass 4499164 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2012 4503285 (Monthly Rollup) 4503263 (Security Only) Important Security Feature Bypass 4499171 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2012 (Server Core installation) 4503285 (Monthly Rollup) 4503263 (Security Only) Important Security Feature Bypass 4499171 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2012 R2 4503276 (Monthly Rollup) 4503290 (Security Only) Important Security Feature Bypass 4499151 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None Windows Server 2012 R2 (Server Core installation) 4503276 (Monthly Rollup) 4503290 (Security Only) Important Security Feature Bypass 4499151 Base: 8.5 Temporal: 7.6 Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Yes None 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
8 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 |
4503276 |
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
Yaron Zinar and Marina Simakov from Preempt
Sergei Glazunov of Google Project Zero
References
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