XSS in Umbraco Cms

CVE-2020-5809

A stored XSS vulnerability exists in Umbraco CMS <= 8.9.1 or current. An authenticated user can inject arbitrary JavaScript code into iframes when editing content using the TinyMCE rich-text editor, as TinyMCE is configured to allow iframes by default in Umbraco CMS.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

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: 0.007 (50.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 50.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2020-5809: held from 0.007 to 0.007.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: +0.000

Affected products

  • Umbraco Cms
  • Umbraco Cms — versions <= 8.9.1 or current (unfixed)

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2020-5809?
CVE-2020-5809 is a medium-severity vulnerability in Umbraco Cms, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2020-12-30.
How severe is CVE-2020-5809?
Medium severity. CVSS v3 base score is 5.4 out of 10.