diff --git a/Marlin/src/feature/binary_protocol.h b/Marlin/src/feature/binary_protocol.h
index 58817f66ba..56f45003a1 100644
--- a/Marlin/src/feature/binary_protocol.h
+++ b/Marlin/src/feature/binary_protocol.h
@@ -242,7 +242,7 @@ public:
       uint8_t protocol() { return (meta >> 4) & 0xF; }
       uint8_t type() { return meta & 0xF; }
       void reset() { token = 0; sync = 0; meta = 0; size = 0; checksum = 0; }
-      uint8_t data[1];
+      uint8_t data[2];
     };
 
     union Footer {