VulnerabilityModified

CVE-2021-34522

Microsoft Defender Remote Code Execution Vulnerability

HIGH 7.8EPSS 2.72%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (2.72%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

Microsoft Defender Remote Code Execution Vulnerability

CVSS 3.1: 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS: 2.72% probability · 86th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Affected: microsoft/malware protection engine
Source: secure@microsoft.com

EPSS trend

EPSS 2.7% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34522
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34522Patch, Vendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.