CVE-2024-35218 Umbraco CMS Vulnerable to Stored XSS on Content Page Through Markdown Editor Preview Pane
Attackers with backoffice access can inject malicious scripts via the Markdown editor preview pane, leading to stored XSS attacks on the website.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2024-35218?
CVE-2024-35218 is a medium-severity cross-site scripting vulnerability in Umbraco Umbraco Cms, published on 21 May 2024. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2024-35218?
8 open source packages ship an affected version, including UmbracoCms.Core. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
UmbracoCms.Core NuGet | From 10.0.0 | 10.8.4 |
UmbracoCms.Core NuGet | From 10.0.0 | 10.8.4 |
UmbracoCms.Core NuGet | From 12.0.0 | 12.3.7 |
UmbracoCms.Core NuGet | From 12.0.0 | 12.3.7 |
UmbracoCms.Core NuGet | From 13.0.0 | 13.1.1 |
UmbracoCms.Core NuGet | From 13.0.0 | 13.1.1 |
2 more packages
UmbracoCms.Core NuGet | From 8.0.0 | 8.18.13 |
UmbracoCms.Core NuGet | From 8.0.0 | 8.18.13 |
Products include Umbraco Umbraco Cms.
How do I fix CVE-2024-35218?
Upgrade UmbracoCms.Core to a fixed version for your release line: 10.8.4, 12.3.7, 13.1.1 or 8.18.13.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2024-35218 being exploited?
There is no known exploitation of CVE-2024-35218 in the wild and no public exploit code.
Other vulnerabilities in Umbraco Umbraco Cms
- CVE-2025-67288 Umbraco CMS has an arbitrary file upload vulnerability
- CVE-2014-10074 File upload in n/a
- CVE-2012-1301 Server-side request forgery in n/a
- CVE-2012-10054 Umbraco CMS < 4.7.1 codeEditorSave.asmx RCE
- CVE-2025-32017 Umbraco has a Management API Vulnerability to Path Traversal With Authenticated Users
Sources
Also known as GHSA-gvpc-3pj6-4m9w.