How severe is CVE-2021-27066?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Microsoft Windows Admin Center

CVE-2021-27066

Windows Admin Center Security Feature Bypass Vulnerability

Published 2021-03-11 · last modified 2026-08-19.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.030 (87.5th percentile), scored 2026-11-04.

Low probability of exploitation in the next 30 days, but still tracked. 88th percentile — 87.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.030 · newest: 0.030 · change: 0.000

Affected products

Microsoft Windows Admin Center — versions 1809.0
Microsoft Windows Admin Center

References

af854a3a-2127-422b-91ae-364da2661108 (Patch, Vendor Advisory)
msrc.microsoft.com/update-guide/vulnerability/CVE-2021-27066 (vendor-advisory, patch)

Frequently asked questions

What is CVE-2021-27066?: CVE-2021-27066 is a medium-severity vulnerability in Microsoft Windows Admin Center. CVSS score: 4.3/10. Published 2021-03-11.
How severe is CVE-2021-27066?: Medium severity. CVSS v3 base score is 4.3 out of 10.