CVE-2021-43890
Microsoft Windows AppX Installer Spoofing Vulnerability
Microsoft WindowsOperating systems
CVSS
7.1HighExploit odds (EPSS)11.3%Chance of exploitation activity in the next 30 days, higher than 95% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
CISA required actionApply updates per vendor instructions. CISA KEV
What fixes it
No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.
Timeline
Description
Microsoft Windows AppX Installer contains a spoofing vulnerability which has a high impacts to confidentiality, integrity, and availability.
Text from CVE List
Affected versions 1
- App Installeraffected: 1.0.0.0 before publicationCVE List
References 7
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890Advisoryvia CVE List
- microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/Advisoryvia CVE List
- nvd.nist.gov/vuln/detail/CVE-2021-43890Referencevia CISA KEV
- bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/Referencevia CVE List
- thehackernews.com/2023/12/microsoft-disables-msix-app-installer.htmlReferencevia CVE List
- github.com/ChrisTitusTech/winutil/pull/26Referencevia CVE List
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-43890Referencevia CVE List