Umbraco CMS versions prior to 4.7.1 are vulnerable to unauthenticated remote code execution via the codeEditorSave.asmx SOAP endpoint, which exposes a SaveDLRScript operation that permits arbitrary file uploads without authentication. By exploiting a path traversal flaw in the fileName parameter, attackers can write malicious ASPX scripts directly into the web-accessible /umbraco/ directory and execute them remotely.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.