diff --git a/ripngd/ripng_zebra.c b/ripngd/ripng_zebra.c
index a48539e..e02b098 100644
--- a/ripngd/ripng_zebra.c
+++ b/ripngd/ripng_zebra.c
@@ -147,7 +147,7 @@
   /* IPv6 prefix. */
   memset (&p, 0, sizeof (struct prefix_ipv6));
   p.family = AF_INET6;
-  p.prefixlen = stream_getc (s);
+  p.prefixlen = MIN(IPV6_MAX_PREFIXLEN, stream_getc (s));
   stream_get (&p.prefix, s, PSIZE (p.prefixlen));
 
   /* Nexthop, ifindex, distance, metric. */