CVE-2025-66625 Umbraco Vulnerable to Improper File Access and Credential Exposure through Dictionary Import Functionality
Backoffice attackers can enumerate server files and potentially expose NTLM hashes via predictable temporary file paths in Umbraco CMS.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-66625?
CVE-2025-66625 is a medium-severity vulnerability in Umbraco Umbraco Cms, published on 9 Dec 2025. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
Umbraco is an ASP.NET CMS. Due to unsafe handling and deletion of temporary files in versions 10.0.0 through 13.12.0, during the dictionary upload process an attacker with access to the backoffice can trigger predictable requests to temporary file paths. The application’s error responses (HTTP 500 when a file exists, 404 when it does not) allow the attacker to enumerate the existence of arbitrary files on the server’s filesystem. This vulnerability does not allow reading or writing file contents. In certain configurations, incomplete clean-up of temporary upload files may additionally expose the NTLM hash of the Windows account running the Umbraco application. This issue is fixed in version 13.12.1.
Which versions are affected by CVE-2025-66625?
2 open source packages ship an affected version, including Umbraco.Cms. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
Umbraco.Cms NuGet | From 10.0.0 | 13.12.1 |
Umbraco.Cms NuGet | From 10.0.0 | 13.12.1 |
Products include Umbraco Umbraco Cms.
How do I fix CVE-2025-66625?
Upgrade Umbraco.Cms to 13.12.1 or later.
Is CVE-2025-66625 being exploited?
There is no known exploitation of CVE-2025-66625 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-hfv2-pf68-m33x.