diff --git a/src/stkutil.h b/src/stkutil.h
index f2e86681..d8415393 100644
--- a/src/stkutil.h
+++ b/src/stkutil.h
@@ -1691,7 +1691,7 @@ struct stk_envelope_event_download {
 		} browser_termination;
 		struct {
 			struct stk_channel channel;
-			unsigned int channel_data_len;
+			unsigned short channel_data_len;
 		} data_available;
 		struct {
 			struct stk_channel channel;