---
id: CVE-2025-66625
title: Umbraco is an ASP.NET CMS
summary: >-
  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
  temp…
severity: medium
cvss: 4.9
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-200
  - CWE-377
  - CWE-552
vendor: umbraco
product: umbraco_cms
affected:
  - 'umbraco_cms >= 10.0.0, < 13.12.1'
patched:
  - umbraco_cms 13.12.1
published: '2025-12-09'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T21:10:00.183'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-66625'
references:
  - url: >-
      https://github.com/umbraco/Umbraco-CMS/commit/7505efd433189037f46547932d4a8b603fd4a615
    label: security-advisories@github.com
  - url: >-
      https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-hfv2-pf68-m33x
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00357
epssPercentile: 0.27803
ingestedAt: '2026-10-14T21:57:04.770Z'
---

## Overview

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.

## Affected

- `umbraco_cms >= 10.0.0, < 13.12.1`

## Remediation

Upgrade past the affected range:

- `umbraco_cms 13.12.1`