Subresource Integrity (SRI) is a W3C recommendation to provide a method to protect website delivery. Sub resource Integrity (SRI) provides a mechanism to check integrity of the resource hosted by third parties interface plug-ins like Content Delivery Networks (CDNs) and verifies that the fetched resource has been delivered to the user without unexpected manipulation. This ensures these assets have not been compromised for hostile purposes. Subresource Integrity (SRI) implemented, but in this server the external scripts are loaded over HTTP.
An attacker can gain access to Content Delivery Networks and cause huge damage the application. If the attacker is one of the persons who had developed one of the CDN used by the application. He can gain access to your system by tweaking the content from CDN.