CVE DATABASE / CVE-2021-1647
CVE-2021-1647
Microsoft Defender Remote Code Execution Vulnerability
CVSS 7.8 · HIGH
⚠ CISA KEV — ACTIVELY EXPLOITED
On the CISA KEV catalog
Confirmed exploited in the wild. Added 2021-11-03.
Federal remediation due 2021-11-17.
Required action: Apply updates per vendor instructions.
Summary
Microsoft Defender Remote Code Execution Vulnerability
CVSS 3.1 breakdown
| Base score | 7.8 (HIGH) |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Attack vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity | HIGH |
| Availability | HIGH |
Affected products
Microsoft windows defenderMicrosoft windows 10 1507Microsoft windows 10 1607Microsoft windows 10 1803Microsoft windows 10 1809Microsoft windows 10 1909Microsoft windows 10 2004Microsoft windows 10 20h2Microsoft windows 7Microsoft windows 8.1Microsoft windows rt 8.1Microsoft windows server 1909Microsoft windows server 2004Microsoft windows server 2008Microsoft windows server 2012Microsoft windows server 2016Microsoft windows server 2019Microsoft windows server 20h2Microsoft security essentialsMicrosoft system center endpoint protection
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References
- 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
Data: NIST NVD + CISA KEV. NVD last modified 2025-10-30. Always verify against the vendor advisory before acting.