Which products and versions are affected by CVE-2021-1647?

Affected: Security Essentials (Microsoft); System Center Endpoint Protection (Microsoft) versions 2012, 2012-r2; Windows Defender (Microsoft). The full list is in the CVE brief.

Is CVE-2021-1647 being exploited in the wild?

It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jan 12, 2021.

Is CVE-2021-1647 in the CISA KEV catalog?

Yes. It was added on Nov 3, 2021 with a federal remediation due date of Nov 17, 2021.

Is there a public exploit for CVE-2021-1647?

Public exploit code is available.

Is there a fix for CVE-2021-1647?

No fixed version is listed yet; check the vendor advisory for mitigations.

How urgently should CVE-2021-1647 be patched?

Brandefense priority: patch immediately, because it is listed as exploited in the wild.

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Vulnerability Intelligence

CVE-2021-1647

HighExploitedPublic exploit

Microsoft Defender Remote Code Execution Vulnerability

Published Jan 18, 2021 · Updated Oct 21, 2025 · Also known as TR-21-0049

Key Facts

Patch immediately

CVE-2021-1647 is a high-severity vulnerability (CVSS 7.8 v3.1) affecting Security Essentials (Microsoft), System Center Endpoint Protection (Microsoft), Windows Defender (Microsoft).
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jan 12, 2021. Public exploit code is available.
EPSS estimates a 40% probability of exploitation in the next 30 days.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

7.8

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

EPSS (30-day exploit likelihood)

40%

Higher than 98.6% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2021-1647 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

Microsoft Defender Remote Code Execution Vulnerability

Known-Exploited Catalog Listings

Catalog	Added	Remediation due	Ransomware use
CISA KEV	Nov 3, 2021	Nov 17, 2021	Not reported
Industry KEV feed	Jan 12, 2021	Nov 17, 2021	Not reported
CIRCL KEV	Nov 3, 2021	Nov 17, 2021	Not reported
ENISA EUVD	Nov 3, 2021	n/a	Not reported

Required action: Apply updates per vendor instructions.

Affected Products

5 affected entries in total

Product	Affected versions	Fixed in
Security EssentialsMicrosoft	See advisory	n/a
System Center Endpoint ProtectionMicrosoft	2012, 2012-r2	n/a
Windows DefenderMicrosoft	See advisory	n/a

Timeline

Added to Industry KEV feed
Jan 12, 2021
Publicly disclosed
Jan 18, 2021
Added to CISA KEV
Nov 3, 2021
Added to CIRCL KEV
Nov 3, 2021
Added to ENISA EUVD
Nov 3, 2021
Last updated
Oct 21, 2025

References

15 more references in the full CVE brief

FAQ

Common Questions.

Microsoft Defender Remote Code Execution Vulnerability
Affected: Security Essentials (Microsoft); System Center Endpoint Protection (Microsoft) versions 2012, 2012-r2; Windows Defender (Microsoft). The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jan 12, 2021.
Yes. It was added on Nov 3, 2021 with a federal remediation due date of Nov 17, 2021.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Is CVE-2021-1647 Running On Your Attack Surface?

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