CVE-2019-1254 — Windows Hyper-V Information Disclosure Vulnerability

Executive Summary

An information disclosure vulnerability exists when Windows Hyper-V writes uninitialized memory to disk. An attacker could exploit the vulnerability by reading a file to recover kernel memory. To exploit the vulnerability, an attacker would first require access to a Hyper-V host. The security update addresses the vulnerability by ensuring Hyper-V properly initializes memory before writing it to disk.

Overview

5.5

CVSS MEDIUM

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Information Disclosure

Released Sep 10 2019

Last Updated Sep 10 2019

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.01326 — 0.68033 percentile

NVD CVSS 5.5 MEDIUM — matches MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:C

ATTACK VECTOR

Local

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

None

AVAILABILITY

None

EXPLOIT CODE MATURITY

Proof-of-Concept

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 5.0

EPSS Score

0.01326

probability of exploitation in the next 30 days

0.68033 percentile - updated 2026-07-25

View on FIRST.org

Affected Products

12 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1607 for x64-based Systems	`4516044 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1703 for x64-based Systems	`4516068 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1709 for x64-based Systems	`4516066 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1803 for x64-based Systems	`4516058 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1809 for x64-based Systems	`4512578 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1903 for x64-based Systems	`4515384 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2016	`4516044 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2016 (Server Core installation)	`4516044 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2019	`4512578 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2019 (Server Core installation)	`4512578 (Security Update)`	Important	Information Disclosure	Yes
Windows Server, version 1803 (Server Core Installation)	`4516058 (Security Update)`	Important	Information Disclosure	Yes
Windows Server, version 1903 (Server Core installation)	`4515384 (Security Update)`	Important	Information Disclosure	Yes

Patches

6 patches

Article	Type	Restart
`4516044`	Security Update	Yes
`4516068`	Security Update	Yes
`4516066`	Security Update	Yes
`4516058`	Security Update	Yes
`4512578`	Security Update	Yes
`4515384`	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

Vladimir Shebaldenkov of UCloud

References

MSRC Advisory MITRE NVD