CVE-2019-1321 — Microsoft Windows CloudStore Elevation of Privilege Vulnerability

Executive Summary

An elevation of privilege vulnerability exists when Windows CloudStore improperly handles file Discretionary Access Control List (DACL). An attacker who successfully exploited this vulnerability could overwrite a targeted file leading to an elevated status. To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system. The security update addresses the vulnerability by correcting how Windows CloudStore handles DACLs.

Overview

5.8

CVSS MEDIUM

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Elevation of Privilege

Released Oct 8 2019

Last Updated Oct 8 2019

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.00902 — 0.55017 percentile

CVSS Vector

ATTACK VECTOR

Local

ATTACK COMPLEXITY

High

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Unchanged

Temporal Score: 5.2

EPSS Score

0.00902

probability of exploitation in the next 30 days

0.55017 percentile - updated 2026-06-20

View on FIRST.org

Affected Products

18 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1703 for 32-bit Systems	`4520010 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1703 for x64-based Systems	`4520010 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1709 for 32-bit Systems	`4520004 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1709 for ARM64-based Systems	`4520004 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1709 for x64-based Systems	`4520004 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1803 for 32-bit Systems	`4520008 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1803 for ARM64-based Systems	`4520008 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1803 for x64-based Systems	`4520008 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1809 for 32-bit Systems	`4519338 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1809 for ARM64-based Systems	`4519338 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1809 for x64-based Systems	`4519338 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1903 for 32-bit Systems	`4517389 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1903 for ARM64-based Systems	`4517389 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1903 for x64-based Systems	`4517389 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2019	`4519338 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2019 (Server Core installation)	`4519338 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server, version 1803 (Server Core Installation)	`4520008 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server, version 1903 (Server Core installation)	`4517389 (Security Update)`	Important	Elevation of Privilege	Yes

Patches

5 patches

Article	Type	Restart
`4520010`	Security Update	Yes
`4520004`	Security Update	Yes
`4520008`	Security Update	Yes
`4519338`	Security Update	Yes
`4517389`	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

k0shl of Qihoo 360 Vulcan team

References

MSRC Advisory MITRE NVD