Vulnerability in Microsoft App Installer
CVE-2021-43890
We have investigated reports of a spoofing vulnerability in AppX installer that affects Microsoft Windows. Microsoft is aware of attacks that attempt to exploit this vulnerability by using specially crafted packages that include the malwar…
EPSS: 0.252 (96.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C.
Affected products
- Microsoft App Installer — versions 1.0.0.0
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
Required action: Apply updates per vendor instructions.
Known ransomware campaign use: yes.
Public proof-of-concept exploits
References
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890 (x_refsource_MISC)
- www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handle…
- thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html
- www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-a…
- github.com/ChrisTitusTech/winutil/pull/26
Frequently asked questions
- What is CVE-2021-43890?
- CVE-2021-43890 is a high-severity vulnerability in Microsoft App Installer. CVSS score: 7.1/10. Published 2021-12-15.
- How severe is CVE-2021-43890?
- High severity. CVSS v3 base score is 7.1 out of 10.
- Is CVE-2021-43890 known to be exploited?
- Yes. CVE-2021-43890 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-12-15), indicating it is being actively exploited. 4 public proof-of-concept repositories are indexed.