Fix https://github.com/XTLS/Xray-core/issues/3288

transport/internet/reality/reality.go

@@ -206,6 +206,9 @@ func UClient(c net.Conn, config *Config, ctx context.Context, dest net.Destinati
 					req, _ = http.NewRequest("GET", string(prefix)+getPathLocked(paths), nil)
 					maps.Unlock()
 				}
+				if req == nil {
+					return
+				}
 				req.Header.Set("User-Agent", fingerprint.Client) // TODO: User-Agent map
 				if first && config.Show {
 					newError(fmt.Sprintf("REALITY localAddr: %v\treq.UserAgent(): %v\n", localAddr, req.UserAgent())).WriteToLog(session.ExportIDToError(ctx))