Szafir SDK Web is a browser plug-in that can run SzafirHost application which download the necessary files when launched. In Szafir SDK Web it is possible to change the URL (HTTP Origin) of the application call location. An unauthenticated attacker can craft a website that is able to launch SzafirHost application with arbitrary arguments via Szafir SDK Web browser addon. No validation will be performed to check whether the address specified in document_base_url parameter is in any way related to the actual address of the calling web application.

The URL address specified in document_base_url parameter is then shown in the application confirmation prompt. When a victim confirms the execution of the application, it will be called in the context of attacker's website URL and might download additional files and libraries from that website. When victim accepts the application execution for the URL showed in the confirmation prompt with the "remember" option before, the prompt won't be shown and the application will be called in the context of URL provided by the attacker without any interaction.

This issue was fixed in version 0.0.17.4.