CVE-2021-34471

mediumpriority · track · 18EPSS 0.005 · 43 %ileEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.51% (43rd) EPSS

CVSS 4.6 · medium

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 Elevation of Privilege Vulnerability

remediations

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

A vendor fix is available.

FixedMicrosoft Malware Protection Enginemsrc_csaf
1.1.18400.4: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.

7.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–high · 3.9–7.8

v2.04.6mediumAV:L/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 3.9 · impact 6.4

v2.03.9lowAV:L/AC:L/Au:N/C:P/I:P/A:P/E:Usecondary · CVSS-BT (t0sche)

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

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/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:L/UI:N/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:L/UI:N/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:L/UI:N/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-269USprimaryCWE-264US

affected products (5)

Products and version ranges known to be affected.

Microsoft Microsoft Malware Protection Engine1.1.0.0 → 1.1.18400.4enisa_euvdEU
Microsoft Corp Microsoft Malware Protection Engine≤ 1.1.18400.4fstec_bduRU
Microsoft Malware Protection Engineall versionsfixedmsrc_csafUS
Microsoft Malware Protection Engine< 1.1.18400.4msrc_csafUS
microsoft malware protection engine< 1.1.18400.4nvdUScpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

msrc_CVE-2021-34471Microsoft Defender Elevation of Privilege Vulnerability2021-08-10csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

also known as (6)

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 2021-08-12modified 2026-08-10

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+6653 more

references (8)

External citations — patches, advisories, analysis.

scry

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