CVE-2021-43890VulnerabilityPublished 12/15/2021Updated 10/24/2026

CVE-2021-43890: Microsoft Windows AppX Installer Spoofing Vulnerability

Affects Microsoft WindowsSource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 12/15/2021
KEV deadline: 12/29/2021
Ransomware: Used in ransomware campaigns
EPSS: 11.3% chance of exploitation in 30 days – higher than 95% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2021-43890 (opens in a new tab)

Description

CVE-2021-43890 is a spoofing vulnerability in Microsoft Windows AppX Installer that impacts confidentiality, integrity, and availability. It has been exploited in the wild and is known to be used in ransomware campaigns. No specific affected versions or patch information is provided in the available data.

Summary

Microsoft Windows AppX Installer contains a spoofing vulnerability identified as CVE-2021-43890. This vulnerability allows an attacker to spoof components or processes related to the AppX Installer, potentially impacting the confidentiality, integrity, and availability of the affected system. The vulnerability has been exploited in the wild and is associated with ransomware campaigns. No detailed technical exploitation methods or affected version ranges are specified in the provided information.

Impact

The vulnerability affects confidentiality, integrity, and availability of Windows systems using the AppX Installer. Exploitation in the wild and use in ransomware campaigns indicate a significant risk to affected systems, potentially allowing attackers to deceive users or systems and execute malicious actions.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no patch or official fix information is provided, users should monitor Microsoft advisories for updates and apply any released patches promptly.

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 09:56:14 UTC

References

Related threats