Umbraco CMS vulnerable to possible injection of HTML in an unintended form

published 2023-12-12 2 y ago modified 2026-06-17 4 mo ago also GHSA-xxc6-35r7-796w , EUVD-2023-3328

cvss: 3.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits: 0; none known

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.

Patch / fix

fixed in 2

nuget Umbraco.CMS 8.18.10, 10.7.0, 12.1.0
umbraco umbraco_cms 8.18.10, 10.7.0, 12.1.0

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	3.5	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N
NVD	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
GitHub	3.1	0.0	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
nuget	Umbraco.CMS	>=8.0.0, <8.18.10 >=9.0.0, <10.7.0 >=11.0.0, <12.1.0	8.18.10 10.7.0 12.1.0

Affected products

umbraco Umbraco-CMS

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

github.com /umbraco/Umbraco-CMS/security/advisories/GHSA-xxc6-35r7-796w
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2023-38694
advisory
github.com /umbraco/Umbraco-CMS
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary