CVE-2023-38694: Umbraco CMS vulnerable to possible injection of HTML in an unintended form

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-12-12 · updated 2026-06-17
Weakness: CWE-79

Description

Umbraco is an ASP.NET content management system (CMS). Starting in version 8.0.0 and prior to versions 8.18.10, 10.7.0, and 12.1.0, a user with access to a specific part of the backoffice is able to inject HTML code into a form where it is not intended. Versions 8.18.10, 10.7.0, and 12.1.0 contain a patch for this issue.

Affected products

Umbraco-CMS: from 8.0.0 before 8.18.10; from 9.0.0 before 10.7.0; from 11.0.0 before 12.1.0 — fixed in 10.7.0, 12.1.0, 8.18.10

How to fix

Upgrade to a fixed version: Umbraco-CMS 10.7.0, 12.1.0, 8.18.10. Check the vendor advisory for mitigations.

References

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