EspoCRM is an open source customer relationship management application. Prior to version 9.3.4, EspoCRM's built-in formula scripting engine allowing updating attachment's sourceId thus allowing an authenticated admin to overwrite the sourceId field on Attachment entities. Because sourceId is concatenated directly into a file path with no sanitization in EspoUploadDir::getFilePath(), an attacker can redirect any file read or write operation to an arbitrary path within the web server's open_basedir scope.

Version 9.3.4 fixes the issue.