diff --git a/engines/net.c b/engines/net.c
index 7a0fe69..cd19535 100644
--- a/engines/net.c
+++ b/engines/net.c
@@ -484,6 +484,9 @@
 {
 	struct udp_seq *us;
 
+	if (io_u->xfer_buflen < sizeof(*us))
+		return;
+
 	us = io_u->xfer_buf + io_u->xfer_buflen - sizeof(*us);
 	us->magic = cpu_to_le64((uint64_t) FIO_UDP_SEQ_MAGIC);
 	us->bs = cpu_to_le64((uint64_t) io_u->xfer_buflen);
@@ -496,6 +499,9 @@
 	struct udp_seq *us;
 	uint64_t seq;
 
+	if (io_u->xfer_buflen < sizeof(*us))
+		return;
+
 	if (nd->seq_off)
 		return;