What is CVE-2020-17021?

CVE-2020-17021 is a medium-severity vulnerability in Microsoft Dynamics 365, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2020-11-11.

How severe is CVE-2020-17021?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Microsoft Dynamics 365

CVE-2020-17021

Microsoft Dynamics 365 (on-premises) Cross-site Scripting Vulnerability

Vulnerability class: XSS (Cross-Site Scripting)

Published 2020-11-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.014 (72.1th percentile), scored 2026-10-03.

Low probability of exploitation in the next 30 days, but still tracked. 72nd percentile — 72.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Microsoft Dynamics 365 — versions 9.0
Microsoft Dynamics 365 (On-Premises) Version 9.0 — versions 9.0.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-17021 (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2020-17021?: CVE-2020-17021 is a medium-severity vulnerability in Microsoft Dynamics 365, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2020-11-11.
How severe is CVE-2020-17021?: Medium severity. CVSS v3 base score is 5.4 out of 10.