CVE-2019-1064: Microsoft Windows AppX Deployment Service (AppXSVC) Privilege Escalation Vulnerability

Vulnerability summary

CVE-2019-1064 is a high (CVSS 7.8) Link Following vulnerability in Microsoft Windows. It is known to be exploited: CISA lists it, first on 15-03-2022. It has been used in ransomware campaigns. EPSS estimates a 6.89% chance of exploitation in the next 30 days, higher than 94% of scored vulnerabilities.

Timeline

1. 12-06-2019
   PublishedVulnerability first disclosed.
2. 15-03-2022
   Added to CISA KEVMicrosoft Windows AppX Deployment Service (AppXSVC) Privilege Escalation Vulnerability
3. 05-04-2022
   CISA remediation dueApply updates per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

Description

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.

• CWE-59Improper Link Resolution Before File Access ('Link Following')The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.