--- sys/netinet/in_mcast.c.orig	2008-11-25 02:59:29.000000000 +0000
+++ sys/netinet/in_mcast.c	2009-09-10 23:55:15.000000000 +0000
@@ -1379,8 +1384,10 @@
 
 	/*
-	 * Remove the gap in the membership array.
+	 * Remove the gap in the membership and filter arrays.
 	 */
-	for (++idx; idx < imo->imo_num_memberships; ++idx)
+	for (++idx; idx < imo->imo_num_memberships; ++idx) {
 		imo->imo_membership[idx-1] = imo->imo_membership[idx];
+		imo->imo_mfilters[idx-1] = imo->imo_mfilters[idx];
+	}
 	imo->imo_num_memberships--;