diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index cded8e8039bd838cdc06aaee030f28a4cf8c3416..45cf32ca4126091656045b586a0a7ad9200212cf 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -3528,6 +3528,9 @@ static int mlxsw_sp_router_fib6_add(struct mlxsw_sp *mlxsw_sp,
 	if (mlxsw_sp->router->aborted)
 		return 0;
 
+	if (rt->rt6i_src.plen)
+		return -EINVAL;
+
 	if (mlxsw_sp_fib6_rt_should_ignore(rt))
 		return 0;