diff --git a/ospf6d/ospf6_asbr.c b/ospf6d/ospf6_asbr.c
index 07061b6f57..0fd6e15ed6 100644
--- a/ospf6d/ospf6_asbr.c
+++ b/ospf6d/ospf6_asbr.c
@@ -1585,7 +1585,11 @@ ospf6_asbr_summary_remove_lsa_and_route(struct ospf6 *ospf6,
 			zlog_debug(
 				"%s: Remove the blackhole route",
 				__func__);
+
 		ospf6_zebra_route_update_remove(aggr->route, ospf6);
+		if (aggr->route->route_option)
+			XFREE(MTYPE_OSPF6_EXTERNAL_INFO,
+			      aggr->route->route_option);
 		ospf6_route_delete(aggr->route);
 		aggr->route = NULL;
 	}
@@ -2736,8 +2740,13 @@ ospf6_summary_add_aggr_route_and_blackhole(struct ospf6 *ospf6,
 					   struct ospf6_external_aggr_rt *aggr)
 {
 	struct ospf6_route *rt_aggr;
+	struct ospf6_route *old_rt = NULL;
 	struct ospf6_external_info *info;
 
+	/* Check if a route is already present. */
+	if (aggr->route)
+		old_rt = aggr->route;
+
 	/* Create summary route and save it. */
 	rt_aggr = ospf6_route_create(ospf6);
 	rt_aggr->type = OSPF6_DEST_TYPE_NETWORK;
@@ -2756,6 +2765,16 @@ ospf6_summary_add_aggr_route_and_blackhole(struct ospf6 *ospf6,
 	/* Add next-hop to Null interface. */
 	ospf6_add_route_nexthop_blackhole(rt_aggr);
 
+	/* Free the old route, if any. */
+	if (old_rt) {
+		ospf6_zebra_route_update_remove(old_rt, ospf6);
+
+		if (old_rt->route_option)
+			XFREE(MTYPE_OSPF6_EXTERNAL_INFO, old_rt->route_option);
+
+		ospf6_route_delete(old_rt);
+	}
+
 	ospf6_zebra_route_update_add(rt_aggr, ospf6);
 }
 
@@ -3024,8 +3043,8 @@ static void ospf6_aggr_handle_external_info(void *data)
 	(void)ospf6_originate_type5_type7_lsas(rt, ospf6);
 }
 
-static void
-ospf6_asbr_summary_config_delete(struct ospf6 *ospf6, struct route_node *rn)
+void ospf6_asbr_summary_config_delete(struct ospf6 *ospf6,
+				      struct route_node *rn)
 {
 	struct ospf6_external_aggr_rt *aggr = rn->info;
 
@@ -3167,14 +3186,6 @@ void ospf6_external_aggregator_free(struct ospf6_external_aggr_rt *aggr)
 		hash_clean(aggr->match_extnl_hash,
 			ospf6_aggr_unlink_external_info);
 
-	if (aggr->route) {
-		if (aggr->route->route_option)
-			XFREE(MTYPE_OSPF6_EXTERNAL_INFO,
-			      aggr->route->route_option);
-
-		ospf6_route_delete(aggr->route);
-	}
-
 	if (IS_OSPF6_DEBUG_AGGR)
 		zlog_debug("%s: Release the aggregator Address(%pFX)",
 						__func__,
diff --git a/ospf6d/ospf6_asbr.h b/ospf6d/ospf6_asbr.h
index 0487bb14c3..0d2a98aeba 100644
--- a/ospf6d/ospf6_asbr.h
+++ b/ospf6d/ospf6_asbr.h
@@ -182,4 +182,6 @@ void ospf6_external_aggregator_free(struct ospf6_external_aggr_rt *aggr);
 void ospf6_unset_all_aggr_flag(struct ospf6 *ospf6);
 void ospf6_fill_aggr_route_details(struct ospf6 *ospf6,
 				   struct ospf6_external_aggr_rt *aggr);
+void ospf6_asbr_summary_config_delete(struct ospf6 *ospf6,
+				      struct route_node *rn);
 #endif /* OSPF6_ASBR_H */
diff --git a/ospf6d/ospf6_top.c b/ospf6d/ospf6_top.c
index eb89a14cd3..db45fa5f5c 100644
--- a/ospf6d/ospf6_top.c
+++ b/ospf6d/ospf6_top.c
@@ -498,6 +498,7 @@ void ospf6_delete(struct ospf6 *o)
 	struct route_node *rn = NULL;
 	struct ospf6_area *oa;
 	struct vrf *vrf;
+	struct ospf6_external_aggr_rt *aggr;
 
 	QOBJ_UNREG(o);
 
@@ -536,8 +537,11 @@ void ospf6_delete(struct ospf6 *o)
 	}
 
 	for (rn = route_top(o->rt_aggr_tbl); rn; rn = route_next(rn))
-		if (rn->info)
-			ospf6_external_aggregator_free(rn->info);
+		if (rn->info) {
+			aggr = rn->info;
+			ospf6_asbr_summary_config_delete(o, rn);
+			ospf6_external_aggregator_free(aggr);
+		}
 	route_table_finish(o->rt_aggr_tbl);
 
 	XFREE(MTYPE_OSPF6_TOP, o->name);