diff --git a/seq/aseqdump/aseqdump.c b/seq/aseqdump/aseqdump.c
index 3630941..85230df 100644
--- a/seq/aseqdump/aseqdump.c
+++ b/seq/aseqdump/aseqdump.c
@@ -698,6 +698,8 @@ static void dump_ump_sysex_event(const unsigned int *ump)
 	dump_ump_sysex_status("SysEx", snd_ump_sysex_msg_status(ump));
 	length = snd_ump_sysex_msg_length(ump);
 	printf(" length %d ", length);
+	if (length > 14)
+		length = 14;
 	for (i = 0; i < length; i++)
 		printf("%s%02x", i ? ":" : "", ump_sysex7_data(ump, i));
 	printf("\n");
@@ -719,6 +721,8 @@ static void dump_ump_sysex8_event(const unsigned int *ump)
 	length = snd_ump_sysex_msg_length(ump);
 	printf(" length %d ", length);
 	printf(" stream %d ", (ump[0] >> 8) & 0xff);
+	if (length > 13)
+		length = 13;
 	for (i = 0; i < length; i++)
 		printf("%s%02x", i ? ":" : "", ump_sysex8_data(ump, i));
 	printf("\n");