Arbitrary file upload in Umbraco CMS - #VU153915
Published: October 7, 2026
Vulnerability identifier: #VU153915
CSH Severity: Medium
CVSS v4: 7.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-434
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to insufficient validation of file during back-office file upload. A remote user can upload a malicious file and execute it on the server.
Affected software
Umbraco CMS
Remediation
Install updates from vendor's website.
Umbraco CMS - addressed in versions 17.7.1, 18.2.1