Microsoft Defender Remote Code Execution Vulnerability
Microsoft Defender contains an unspecified vulnerability that allows for remote code execution.
- Vendor
- Microsoft
- Product
- Defender
- CVSS
- 7.8
- EPSS (exploit probability)
- 39.7%
- Status
- kev
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2021-1647 being exploited?
Yes. CISA added CVE-2021-1647 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 39.7% (scored October 17, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-11-13. Full cross-catalog view: /kev-comparison
CVE-2021-1647 timeline
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
What to do
CISA required actionApply updates per vendor instructions.
US federal civilian agencies must remediate by (14 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Microsoft Defender CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2026-45498 Microsoft Defender Denial of Service Vulnerability | [ MEDIUM ] | 4.0 | 63.1% | |
| CVE-2026-41091 Microsoft Defender Link Following Vulnerability | [ HIGH ] | 7.8 | 8.2% | |
| CVE-2026-33825 Microsoft Defender Antimalware Platform Local Privilege Escalation (BlueHammer)ransomware usewrite-up | [ HIGH ] | 7.8 | 6.9% | |
| CVE-2022-44698 Microsoft Defender SmartScreen Security Feature Bypass Vulnerabilityransomware use | [ MEDIUM ] | 5.4 | 75.0% |