OnlyPatch
Windows Hyper-V

CVE-2019-0635 — Windows Hyper-V Information Disclosure Vulnerability

Important CVSS 6.2 EPSS 0.02435 2019-02 archive

Executive Summary

An information disclosure vulnerability exists when Windows Hyper-V on a host operating system fails to properly validate input from an authenticated user on a guest operating system. To exploit the vulnerability, an attacker on a guest operating system could run a specially crafted application that could cause the Hyper-V host operating system to disclose memory information. An attacker who successfully exploited the vulnerability could gain access to information on the Hyper-V host operating system. The security update addresses the vulnerability by correcting how Hyper-V validates guest operating system user input.

Overview

6.2
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Information Disclosure
Released Feb 12 2019
Last Updated Feb 12 2019
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.02435 — 0.82573 percentile
NVD CVSS 6.2 MEDIUM — differs from MSRC

CVSS Vector

CVSS:3.0/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C
ATTACK VECTOR
Adjacent_network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
High
USER INTERACTION
None
SCOPE
Changed
CONFIDENTIALITY
High
INTEGRITY
None
AVAILABILITY
None
EXPLOIT CODE MATURITY
Proof-of-Concept
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 4.9

EPSS Score

0.02435
probability of exploitation in the next 30 days
0.82573 percentile - updated 2026-07-25
View on FIRST.org

Affected Products

12 affected products
Product KB Article Severity Impact Restart Required
Windows 10 for x64-based Systems 4487018 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1607 for x64-based Systems 4487026 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1703 for x64-based Systems 4487020 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1709 for x64-based Systems 4486996 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1803 for x64-based Systems 4487017 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1809 for x64-based Systems 4487044 (Security Update) Important Information Disclosure Yes
Windows 7 for x64-based Systems Service Pack 1 4486563 (Monthly Rollup) 4486564 (Security Only) Important Information Disclosure 4480970 Base: 5.4 Temporal: 4.9 Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C Yes None Windows 8.1 for x64-based systems 4487000 (Monthly Rollup) 4487028 (Security Only) Important Information Disclosure 4480963 Base: 5.4 Temporal: 4.9 Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2008 for x64-based Systems Service Pack 2 4487023 (Monthly Rollup) 4487019 (Security Only) Important Information Disclosure 4480968 Base: 5.4 Temporal: 4.9 Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 4487023 (Monthly Rollup) 4487019 (Security Only) Important Information Disclosure 4480968 Base: 5.4 Temporal: 4.9 Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2008 R2 for x64-based Systems Service Pack 1 4486563 (Monthly Rollup) 4486564 (Security Only) Important Information Disclosure 4480970 Base: 5.4 Temporal: 4.9 Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 4486563 (Monthly Rollup) 4486564 (Security Only) Important Information Disclosure 4480970 Base: 5.4 Temporal: 4.9 Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2012 4487025 (Monthly Rollup) 4486993 (Security Only) Important Information Disclosure Base: 5.4 Temporal: 4.9 Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2012 (Server Core installation) 4487025 (Monthly Rollup) 4486993 (Security Only) Important Information Disclosure Base: 5.4 Temporal: 4.9 Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2012 R2 4487000 (Monthly Rollup) 4487028 (Security Only) Important Information Disclosure 4480963 Base: 5.4 Temporal: 4.9 Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2012 R2 (Server Core installation) 4487000 (Monthly Rollup) 4487028 (Security Only) Important Information Disclosure 4480963 Base: 5.4 Temporal: 4.9 Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2016 4487026 (Security Update) Important Information Disclosure Yes
Windows Server 2016 (Server Core installation) 4487026 (Security Update) Important Information Disclosure Yes
Windows Server 2019 4487044 (Security Update) Important Information Disclosure Yes
Windows Server 2019 (Server Core installation) 4487044 (Security Update) Important Information Disclosure Yes
Windows Server, version 1709 (Server Core Installation) 4486996 (Security Update) Important Information Disclosure Yes
Windows Server, version 1803 (Server Core Installation) 4487017 (Security Update) Important Information Disclosure Yes

Patches

6 patches
Article Type Restart
4487018 Security Update Yes
4487026 Security Update Yes
4487020 Security Update Yes
4486996 Security Update Yes
4487017 Security Update Yes
4487044 Security Update Yes

Known Exploits

Acknowledgments

Peter Hlavaty ( @zer0mem

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