Add Content-Security-Policy header

server/core/response.go

@@ -69,6 +69,7 @@ func (r *Response) commonHeaders() {
 	r.writer.Header().Set("X-XSS-Protection", "1; mode=block")
 	r.writer.Header().Set("X-Content-Type-Options", "nosniff")
 	r.writer.Header().Set("X-Frame-Options", "DENY")
+	r.writer.Header().Set("Content-Security-Policy", "default-src 'self'; img-src *; media-src *; frame-src *")
 }
 
 // NewResponse returns a new Response.