diff --git a/src/udp_bridge.h b/src/udp_bridge.h
index b99a2fb..1b33ea3 100644
--- a/src/udp_bridge.h
+++ b/src/udp_bridge.h
@@ -242,6 +242,9 @@ class BridgeUDP final: public UDP {
 
     int read() override {
         uint8_t c;
+        if (!temp_buffer.available() && !available()) {
+            return -1;
+        }
         read(&c, 1);
         return c;
     }