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High 7.8Known exploited (CISA KEV)Published Jan 12, 2021
CVE-2021-1647Microsoft Defender Remote Code Execution Vulnerability
Updated under an hour ago ()
Does this affect you?
It affects Microsoft System Center Endpoint Protection and 2 other products. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Nov 3, 2021; federal agencies had to remediate by Nov 17, 2021. Treat that date as your deadline.
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Microsoft Defender Remote Code Execution Vulnerability
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
- Weakness (CWE)
- Not given
- Known exploited
- Added to CISA KEV Nov 3, 2021; federal remediation due Nov 17, 2021Apply updates per vendor instructions.
- EPSS (exploitation in the next 30 days)
- 39.65% (percentile 99)
- Assigned by
- microsoft
- NVD analysis
- Analyzed
- Record last updated
- Oct 21, 2025
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Microsoft Microsoft System Center Endpoint Protection microsoft:system_center_endpoint_protection | all versions | CNA record |
Microsoft Microsoft Security Essentials microsoft:security_essentials | all versions | CNA record |
Microsoft Windows Defender microsoft:windows_defender | all versions | CNA record |
microsoft windows_defender microsoft:windows_defender | all versions | NVD |
microsoft security_essentials microsoft:security_essentials | all versions | NVD |
microsoft system_center_endpoint_protection microsoft:system_center_endpoint_protection | all versions; 2012; 2012 | NVD |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-1647vendor-advisory, patch
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1647patch, vendor-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1647us-government-resource
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.