What is CVE-2021-20099?

CVE-2021-20099 is a medium-severity vulnerability in Microsoft Windows. CVSS score: 6.7/10. Published 2021-06-28.

How severe is CVE-2021-20099?

Medium severity. CVSS v3 base score is 6.7 out of 10.

Vulnerability in Microsoft Windows

CVE-2021-20099

Nessus Agent 8.2.4 and earlier for Windows were found to contain multiple local privilege escalation vulnerabilities which could allow an authenticated, local administrator to run specific Windows executables as the Nessus host. This is different than CVE-2021-20100.

Published 2021-06-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.7 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (34.9th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 34.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Microsoft Windows
Tenable Nessus
Nessus Agent — versions Nessus Agent 8.2.4 and earlier

References

www.tenable.com/security/tns-2021-12 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-20099?: CVE-2021-20099 is a medium-severity vulnerability in Microsoft Windows. CVSS score: 6.7/10. Published 2021-06-28.
How severe is CVE-2021-20099?: Medium severity. CVSS v3 base score is 6.7 out of 10.