CVE-2026-46609 Umbraco.Cms: XSS/HTML Injection in Umbraco Backoffice confirmation dialog
Authenticated users can inject HTML into confirmation dialogs, potentially leading to script execution or account takeover in Umbraco CMS.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-46609?
CVE-2026-46609 is a medium-severity cross-site scripting vulnerability in Umbraco Umbraco Cms, published on 10 Jun 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Umbraco is an ASP.NET CMS. From version 14.0.0 to before version 17.4.0, authenticated users are able to inject HTML into an input field, which is rendered in the confirmation dialog without proper output encoding. This issue has been patched in version 17.4.0.
Weakness: CWE-79
Which versions are affected by CVE-2026-46609?
2 open source packages ship an affected version, including Umbraco.Cms. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
Umbraco.Cms NuGet | From 14.0.0 | 17.4.0 |
Umbraco.Cms NuGet | From 14.0.0 | 17.4.0 |
Products include Umbraco Umbraco Cms.
How do I fix CVE-2026-46609?
Upgrade Umbraco.Cms to 17.4.0 or later.
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-2026-46609 being exploited?
There is no known exploitation of CVE-2026-46609 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-vr9v-27gg-qgx4.