CVE-2021-1647

CVE-2021-1647 is a high-severity (CVSS 7.8) vulnerability in Microsoft Defender. CISA added it to the Known Exploited Vulnerabilities catalog on November 3, 2021, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by November 17, 2021. CISA does not currently list it as used in ransomware campaigns. Microsoft has 390 vulnerabilities in the KEV catalog, 117 of them linked to ransomware.

Microsoft Defender Remote Code Execution Vulnerability

CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-1647
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1647
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1647