diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index ba506e2..aa1234b 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -773,6 +773,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)
 							  cmd->temporary ? RS_TEMPORARY : RS_EPHEMERAL);
 	}
 
+	initStringInfo(&reply_message);
 	initStringInfo(&output_message);
 
 	if (cmd->kind == REPLICATION_KIND_LOGICAL)