diff --git a/lib/socket.c b/lib/socket.c
index d97798a..d73859c 100644
--- a/lib/socket.c
+++ b/lib/socket.c
@@ -640,6 +640,11 @@ iscsi_write_to_socket(struct iscsi_context *iscsi)
 				return 0;
 			}
 			/* pop first element of the outqueue */
+			if (iscsi_serial32_compare(iscsi->outqueue->cmdsn, iscsi->expcmdsn) < 0) {
+				iscsi_set_error(iscsi, "iscsi_write_to_scoket: outqueue[0]->cmdsn < expcmdsn (%08x < %08x)",
+				                iscsi->outqueue->cmdsn, iscsi->expcmdsn);
+				return -1;
+			}
 			iscsi->outqueue_current = iscsi->outqueue;
 			ISCSI_LIST_REMOVE(&iscsi->outqueue, iscsi->outqueue_current);
 			if (!(iscsi->outqueue_current->flags & ISCSI_PDU_DELETE_WHEN_SENT)) {