Severity by source
AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L
Lifecycle Timeline
4DescriptionGitHub Advisory
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.
Analysis
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.
Technical ContextAI
Unrestricted file upload allows attackers to upload malicious files (web shells, executables) that can then be executed on the server. This vulnerability is classified as Unrestricted Upload of File with Dangerous Type (CWE-434).
RemediationAI
A vendor patch is available — apply it immediately. Validate file types by content (magic bytes), not just extension. Store uploads outside the web root. Use random filenames. Scan uploads for malware.
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External POC / Exploit Code
Leaving vuln.today
EUVD-2025-16778
GHSA-fr6r-p8hv-x3c4