diff --git a/sys/netinet/ip_mroute.c b/sys/netinet/ip_mroute.c
index 727a7c2a82e3..d24b0f5bd66a 100644
--- a/sys/netinet/ip_mroute.c
+++ b/sys/netinet/ip_mroute.c
@@ -740,7 +740,7 @@ X_ip_mrouter_done(void)
 	    if_allmulti(ifp, 0);
 	}
     }
-    bzero((caddr_t)V_viftable, sizeof(V_viftable));
+    bzero((caddr_t)V_viftable, sizeof(V_viftable) * MAXVIFS);
     V_numvifs = 0;
     V_pim_assert_enabled = 0;