CVE-2021-42298

highpriority · track · 39EPSS 0.058 · 93 %ileEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

5.85% (93rd) EPSS

CVSS 9.3 · high

Is it mine?

5 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · msrc_csaf

EPSS · scored 2026-10-27

Microsoft Defender Remote Code Execution Vulnerability

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedMicrosoft Malware Protection Enginemsrc_csaf
1.1.18700.3:Security Update:https://docs.microsoft.com/en-us/microsoft-365/security/defender-endpoint/manage-updates-baselines-microsoft-defender-antivirus?view=o365-worldwide
https://docs.microsoft.com/en-us/microsoft-365/security/defender-endpoint/manage-updates-baselines-microsoft-defender-antivirus?view=o365-worldwide

cvss

Technical severity, 0–10. One row per scoring source.

9.3

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.09.3highAV:N/AC:M/Au:N/C:C/I:C/A:Cprimary · NVD / NIST USexploitability 8.6 · impact 10

v2.09.3highAV:N/AC:M/Au:N/C:C/I:C/A:C/E:Hsecondary · CVSS-BT (t0sche)

v3.17.8highAV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · secure@microsoft.com USexploitability 1.8 · impact 5.9

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:Csecondary · Microsoft Security Response Center US

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:Csecondary · ENISA EU

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · NVD / NIST USexploitability 1.8 · impact 5.9

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-94USprimaryCWE-94US

affected products (5)

Products and version ranges known to be affected.

Microsoft Microsoft Malware Protection Engine1.1.0.0 → 1.1.18700.3enisa_euvdEU
Microsoft Corp Microsoft Malware Protection Engine≤ 1.1.18700.3fstec_bduRU
Microsoft Malware Protection Engineall versionsfixedmsrc_csafUS
Microsoft Malware Protection Engine< 1.1.18700.3msrc_csafUS
microsoft malware protection engine< 1.1.18700.3nvdUScpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

msrc_CVE-2021-42298Microsoft Defender Remote Code Execution Vulnerability2021-11-09csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu msrc_csaf nvd NVD CVE.org MITRE

published 2021-11-10modified 2026-08-19

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+10438 more

references (7)

External citations — patches, advisories, analysis.

scry

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