CVE-2020-5809

5.4 mediumEPSS 0.7%

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.

Severity

CVSS 3.1

5.4 medium

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS: 0.7% chance of exploitation in the next 30 days; higher than 52% of CVEs (scores of 2026-10-31)
CWE: CWE-79
Published: 2020-12-30
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

umbraco:umbraco_cms

References

https://www.tenable.com/security/research/tra-2020-59
https://www.tenable.com/security/research/tra-2020-59

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