CVE-2025-66625: umbraco cms Information Disclosure

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.

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CVSS v3.1 Score

4.9

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Weakness Type (CWE)

CWE-200 CWE-200

CWE-377 CWE-377

CWE-552 CWE-552

Affected Products

Vendor	Product	Versions
umbraco	umbraco_cms	10.0.0 — 13.12.1

References

Advisories & Patches

https://github.com/umbraco/Umbraco-CMS/commit/7505efd433189037f46547932d4a8b603fd4a615 https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-hfv2-pf68-m33x

Frequently Asked Questions

What is CVE-2025-66625? +

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. It has a CVSS v3.1 base score of 4.9 (MEDIUM).

How severe is CVE-2025-66625? +

CVE-2025-66625 has a CVSS v3.1 score of 4.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-66625? +

CVE-2025-66625 affects products from umbraco, specifically: umbraco_cms. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-66625? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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