CVE-2024-35218

Umbraco CMS Vulnerable to Stored XSS on Content Page Through Markdown Editor Preview Pane

4.2 MediumFix available

Umbraco CMS is an ASP.NET CMS used by more than 730.000 websites. Stored Cross-site scripting (XSS) enable attackers that have access to backoffice to bring malicious content into a website or application. This vulnerability has been patched in version(s) 8.18.13, 10.8.4, 12.3.7, 13.1.1 by implementing IHtmlSanitizer.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: High
User interaction: Required

What an attacker can affect

Confidentiality: High
Integrity: None
Availability: None

Exploit likelihood

0.35%Up 0.3 points since May 22, 2024

What each source reports

CVE List Score used 4.2

Umbraco CMS Vulnerable to Stored XSS on Content Page Through Markdown Editor Preview Pane

Record: CVE-2024-35218
CVSS 3.1: 4.2 MediumCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N
Weakness: CWE-79
Updated: 2026-11-02

EUVDEUVD-2024-1633 4.2

Record: EUVD-2024-1633
CVSS 3.1: 4.2 MediumCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N
Updated: 2026-11-03

GitHub AdvisoriesGHSA-gvpc-3pj6-4m9w 4.2

Umbraco CMS Vulnerable to Stored XSS on Content Page Through Markdown Editor Preview Pane

Impact

Stored Cross-site scripting (XSS) enable attackers that have access to backoffice to bring malicious content into a website or application.

Affected versions

Umbraco CMS >= 8.00

Patches

This is fixed in 8.18.13, 10.8.4, 12.3.7, 13.1.1 by implementing IHtmlSanitizer

Record: GHSA-gvpc-3pj6-4m9w
CVSS 3.1: 4.2 MediumCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N
Weakness: CWE-79
Updated: 2026-11-02

NVD 4.2

Record: CVE-2024-35218
CVSS 3.1: 4.2 MediumCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N
CVSS 3.1: 4.8 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Weakness: CWE-79
Updated: 2026-11-02

OSV 4.2

Umbraco CMS Vulnerable to Stored XSS on Content Page Through Markdown Editor Preview Pane

Record: CVE-2024-35218
CVSS 3.1: 4.2 MediumCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N
Weakness: CWE-79
Updated: 2026-11-02

OSVGHSA-gvpc-3pj6-4m9w 4.2

Umbraco CMS Vulnerable to Stored XSS on Content Page Through Markdown Editor Preview Pane

Impact

Stored Cross-site scripting (XSS) enable attackers that have access to backoffice to bring malicious content into a website or application.

Affected versions

Umbraco CMS >= 8.00

Patches

This is fixed in 8.18.13, 10.8.4, 12.3.7, 13.1.1 by implementing IHtmlSanitizer

Record: GHSA-gvpc-3pj6-4m9w
CVSS 3.1: 4.2 MediumCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N
Weakness: CWE-79
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`UmbracoCms.Core` NuGet	8.0.0 up to 8.18.13	8.18.13
`UmbracoCms.Core` NuGet	10.0.0 up to 10.8.4	10.8.4
`UmbracoCms.Core` NuGet	12.0.0 up to 12.3.7	12.3.7
`UmbracoCms.Core` NuGet	13.0.0 up to 13.1.1	13.1.1
`UmbracoCms.Core` NuGet	8.0.0 up to 8.18.13, plus listed versions 8.0.18.0.28.0.38.1.08.1.1 Show 45 moreShow less 8.1.28.1.38.1.48.1.58.1.68.10.08.10.0-rc8.10.18.10.28.10.38.11.08.11.0-rc8.11.18.11.28.11.38.12.08.12.0-rc8.12.18.12.28.12.38.13.08.13.0-rc8.13.18.14.08.14.0-rc8.14.18.14.28.14.38.14.48.15.08.15.0-rc8.15.18.15.28.15.38.16.08.16.0-rc8.17.08.17.0-rc8.17.0-rc28.17.18.17.28.18.08.18.0-rc8.18.0-rc28.18.1	8.18.13

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, published	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2024-35218 is a medium vulnerability (CVSS 4.2) in Umbraco Cms, published May 21, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.35%, the 29th percentile. Fixed in UmbracoCms.Core 8.18.13.

References

This page doesn't list everything

Left out here: 54 versions. The JSON record has them.