CVE-2025-66625

Umbraco Vulnerable to Improper File Access and Credential Exposure through Dictionary Import Functionality

Published Dec 9, 2025 CVSS 3.1 · 4.9 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Github GHSA Github GHSA GHSA-hfv2-pf68-m33x Umbraco Vulnerable to Improper File Access and Credential Exposure in Dictionary Import Functionality
History
Type Values Removed Values Added
CPEs cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Microsoft
Microsoft windows
Umbraco
Umbraco umbraco
Umbraco umbraco Cms
Vendors & Products Microsoft
Microsoft windows
Umbraco
Umbraco umbraco
Umbraco umbraco Cms
Type Values Removed Values Added
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.
Title Umbraco Vulnerable to Improper File Access and Credential Exposure through Dictionary Import Functionality
Weaknesses CWE-200
CWE-377
CWE-552
References
Metrics cvssV3_1

{'score': 4.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Dec 12, 2025, 8:33 PM
Reserved
Dec 5, 2025, 3:18 PM
Status
Analyzed
Published
Dec 9, 2025, 8:15 PM
Modified
Oct 14, 2026, 9:10 PM