CVE-2019-1064
CVE-2019-1064 is a security flaw in Microsoft Windows, Microsoft’s operating system for PCs and servers. Someone who already has a foothold can use Microsoft Windows to take full control of the machine. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 15 Mar 2022, and says ransomware gangs have used it.[1]
Microsoft Windows is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Fixed in version publication.
Description
CISA calls it an appX deployment service (appXSVC) privilege escalation in Microsoft Windows. In its words: “A privilege escalation vulnerability exists when Windows AppXSVC improperly handles hard links. An attacker who successfully exploited this vulnerability could run processes in an elevated context.”[1]
The CVE record adds: “An elevation of privilege vulnerability exists when Windows AppX Deployment Service (AppXSVC) improperly handles hard links. An attacker who successfully exploited this vulnerability could run processes in an elevated context. An attacker could then install programs; view, change or delete data. 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 AppX Deployment Service handles hard links.”[2]
The underlying weakness is CWE-59, in MITRE’s list of common software weaknesses.
It scores 7.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| Windows 10 Version 1703 | publication |
| Windows 10 Version 1803 | publication |
| Windows Server, version 1803 (Server Core Installation) | publication |
| Windows 10 Version 1809 | publication |
| Windows Server 2019 | publication |
| Windows Server 2019 (Server Core installation) | publication |
| Windows 10 Version 1709 for 32-bit Systems | publication |
| Windows 10 Version 1709 | publication |
Every device with Microsoft Windows needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 15 Mar 2022, 1,007 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 5 Apr 2022 to fix it.[1] CISA says ransomware gangs have used it.
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 7%. That’s in the top 6% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Microsoft has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Update Microsoft Windows now.On Windows: Settings, Windows Update, Check for updates, then restart. Office updates come the same way, or from any Office app: File, Account, Update Options. Then turn on automatic updates, so the next fix arrives on its own.
- Check you’re on publication or later.Fixed in version publication. Anything older is what attackers are going after.
- If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks, noting that ransomware gangs have used it.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 7%.[4] |
See also
Other Microsoft Windows flaws
- CVE-2026-96951: command injection ·
- CVE-2026-85880: heap-based buffer overflow ·
- CVE-2026-81963: link following ·
- CVE-2008-4250: buffer overflow ·
- CVE-2026-32202: protection mechanism failure ·
- CVE-2025-60710: link following ·
Similar flaws
- CVE-2015-5287, Red Hat Automatic Bug Reporting Tool: privilege escalation ·
- CVE-2025-48384, Git: link following ·
Added the same day
- CVE-2020-5135, SonicWall SonicOS: buffer overflow ·
- CVE-2019-1405, Microsoft Windows: universal plug and play (UPnP) service privilege escalation ·
- CVE-2019-1322, Microsoft Windows: privilege escalation ·
- CVE-2019-1315, Microsoft Windows: error reporting manager privilege escalation ·
- CVE-2019-1253, Microsoft Windows: appX deployment server privilege escalation ·
Every Microsoft flaw on CISA’s list · Everything added in March 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Microsoft Windows AppX Deployment Service (AppXSVC) Privilege Escalation Vulnerability”. Known Exploited Vulnerabilities Catalog, added 15 Mar 2022.
- ^ National Institute of Standards and Technology. “CVE-2019-1064 Detail”. National Vulnerability Database, published 12 Jun 2019.
- ^ Microsoft. Advisories and fixes: msrc.microsoft.com, portal.msrc.microsoft.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.069, percentile 94.1, 31 Oct 2026.
- CVE Program. “CVE-2019-1064”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.