CVE-2025-48953: umbraco cms File Upload RCE — Fix

Description

Umbraco is an ASP.NET content management system (CMS). Starting in version 14.0.0 and prior to versions 15.4.2 and 16.0.0, it's possible to upload a file that doesn't adhere with the configured allowable file extensions via a manipulated API request. The issue is patched in versions 15.4.2 and 16.0.0. No known workarounds are available.

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CVSS v3.1 Score

5.5

MEDIUM

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

Weakness Type (CWE)

CWE-434 Unrestricted Upload

Affected Products

Vendor	Product	Versions
umbraco	umbraco_cms	14.0.0 — 15.4.2

References

Advisories & Patches

https://github.com/umbraco/Umbraco-CMS/commit/d920e93d1ee29dc3301697e444f53e8cd5db3cf9 https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-fr6r-p8hv-x3c4

Frequently Asked Questions

What is CVE-2025-48953? +

Umbraco is an ASP.NET content management system (CMS). Starting in version 14.0.0 and prior to versions 15.4.2 and 16.0.0, it's possible to upload a file that doesn't adhere with the configured allowable file extensions via a manipulated API request. The issue is patched in versions 15.4.2 and 16.0.0. No known workarounds are available. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-48953? +

CVE-2025-48953 has a CVSS v3.1 score of 5.5 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-2025-48953? +

CVE-2025-48953 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-2025-48953? +

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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