CVE-2019-0786 — Hyper-V vSMB Remote Code Execution Vulnerability

Executive Summary

A remote code execution vulnerability exists when Windows Hyper-V on a host server fails to properly validate vSMB packet data. An attacker who successfully exploited these vulnerabilities could execute arbitrary code on a target operating system. To exploit these vulnerabilities, an attacker running inside a virtual machine could run a specially crafted application that could cause the Hyper-V host operating system to execute arbitrary code. The update addresses the vulnerabilities by correcting how Windows Hyper-V validates vSMB packet data.

Overview

9.8

CVSS CRITICAL

Critical

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Remote Code Execution

Released Apr 9 2019

Last Updated Apr 9 2019

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.06999 — 0.93479 percentile

NVD CVSS 9.8 CRITICAL — differs from MSRC

CVSS Vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C

ATTACK VECTOR

Network

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

None

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

High

EXPLOIT CODE MATURITY

Proof-of-Concept

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 7.0

EPSS Score

0.06999

probability of exploitation in the next 30 days

0.93479 percentile - updated 2026-07-25

View on FIRST.org

Affected Products

13 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1709 for 32-bit Systems	`4493441 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1709 for ARM64-based Systems	`4493441 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1709 for x64-based Systems	`4493441 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1803 for 32-bit Systems	`4493464 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1803 for ARM64-based Systems	`4493464 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1803 for x64-based Systems	`4493464 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1809 for 32-bit Systems	`4493509 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1809 for ARM64-based Systems	`4493509 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1809 for x64-based Systems	`4493509 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2019	`4493509 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2019 (Server Core installation)	`4493509 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server, version 1709 (Server Core Installation)	`4493441 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server, version 1803 (Server Core Installation)	`4493464 (Security Update)`	Critical	Remote Code Execution	Yes

Patches

3 patches

Article	Type	Restart
`4493441`	Security Update	Yes
`4493464`	Security Update	Yes
`4493509`	Security Update	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

None

References

MSRC Advisory MITRE NVD