What is CVE-2025-48953?

CVE-2025-48953 is a medium-severity vulnerability in Umbraco Umbraco-Cms, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 5.5/10. Published 2025-06-03.

How severe is CVE-2025-48953?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Arbitrary file upload in Umbraco Umbraco-Cms

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.

Vulnerability class: Unrestricted File Upload

Published 2025-06-03 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.002 (9.1th percentile), scored 2026-11-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 9th percentile — 9.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Umbraco Umbraco-Cms — versions >= 14.0.0, < 15.4.2
Umbraco Cms

Weakness classification (CWE)

CWE-434 — Unrestricted Upload of File with Dangerous Type

References

github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-fr6r-p8hv-x3c4 (Patch, Third Party Advisory)
github.com/umbraco/Umbraco-CMS/commit/d920e93d1ee29dc3301697e444f53e8cd5db3cf9 (Patch)

Frequently asked questions

What is CVE-2025-48953?: CVE-2025-48953 is a medium-severity vulnerability in Umbraco Umbraco-Cms, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 5.5/10. Published 2025-06-03.
How severe is CVE-2025-48953?: Medium severity. CVSS v3 base score is 5.5 out of 10.