What is CVE-2020-20389?

CVE-2020-20389 is a medium-severity vulnerability in Get-Simple Getsimplecms, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2021-06-23.

How severe is CVE-2020-20389?

Medium severity. CVSS v3 base score is 4.8 out of 10.

XSS in Get-Simple Getsimplecms

CVE-2020-20389

Cross Site Scripting (XSS) vulnerability in GetSimpleCMS 3.4.0a in admin/edit.php.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-06-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.006 (46.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Get-Simple Getsimplecms — versions 3.4.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/GetSimpleCMS/GetSimpleCMS/issues/1321 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2020-20389?: CVE-2020-20389 is a medium-severity vulnerability in Get-Simple Getsimplecms, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2021-06-23.
How severe is CVE-2020-20389?: Medium severity. CVSS v3 base score is 4.8 out of 10.