# 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.

- **Severity:** Medium 4.9 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Dec 2025
- **Updated:** 12 Dec 2025
- **Also known as:** GHSA-hfv2-pf68-m33x

## 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.

Weakness: CWE-552 (Files or Directories Accessible to External Parties), CWE-377 (DEPRECATED: Insecure Temporary File), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2025-66625?

2 open source packages ship an affected version, including Umbraco.Cms. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Umbraco.Cms` | NuGet | From 10.0.0 | 13.12.1 |
| `Umbraco.Cms` | NuGet | From 10.0.0 | 13.12.1 |

Products: 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](https://insights.sbomify.com/CVE-2025-67288/): Umbraco CMS has an arbitrary file upload vulnerability (critical 10.0)
- [CVE-2014-10074](https://insights.sbomify.com/CVE-2014-10074/): File upload in n/a (critical 9.8)
- [CVE-2012-1301](https://insights.sbomify.com/CVE-2012-1301/): Server-side request forgery in n/a (critical 9.8)
- [CVE-2012-10054](https://insights.sbomify.com/CVE-2012-10054/): Umbraco CMS < 4.7.1 codeEditorSave.asmx RCE (critical 9.3)
- [CVE-2025-32017](https://insights.sbomify.com/CVE-2025-32017/): Umbraco has a Management API Vulnerability to Path Traversal With Authenticated Users (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-66625 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2025-66625 in the wild and no public exploit code.

Affected packages and fixed versions:
- Umbraco.Cms (NuGet): affected from 10.0.0; fixed in 13.12.1
- Umbraco.Cms (NuGet): affected from 10.0.0; fixed in 13.12.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-66625/ (Markdown: https://insights.sbomify.com/CVE-2025-66625/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-66625
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-66625
- OSV: https://osv.dev/vulnerability/CVE-2025-66625

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-66625/
Summaries are generated and may contain mistakes; the official description above is the record.