diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index 99b50a5799c0..99b08c482581 100644
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -1119,7 +1119,7 @@ tcp6_ctlinput(cmd, sa, d)
 		inc.inc_isipv6 = 1;
 		syncache_unreach(&inc, &th);
 	} else
-		in6_pcbnotify(&tcb, sa, 0, (struct sockaddr *)sa6_src,
+		in6_pcbnotify(&tcb, sa, 0, (const struct sockaddr *)sa6_src,
 			      0, cmd, notify);
 }
 #endif /* INET6 */
diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c
index 99b50a5799c0..99b08c482581 100644
--- a/sys/netinet/tcp_timewait.c
+++ b/sys/netinet/tcp_timewait.c
@@ -1119,7 +1119,7 @@ tcp6_ctlinput(cmd, sa, d)
 		inc.inc_isipv6 = 1;
 		syncache_unreach(&inc, &th);
 	} else
-		in6_pcbnotify(&tcb, sa, 0, (struct sockaddr *)sa6_src,
+		in6_pcbnotify(&tcb, sa, 0, (const struct sockaddr *)sa6_src,
 			      0, cmd, notify);
 }
 #endif /* INET6 */