diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 26dcdec9e3a5..8fd154e5f079 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -1710,6 +1710,9 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, uns
 			return -EINVAL;
 		if (get_user(v, (u32 __user *)optval))
 			return -EFAULT;
+		/* "pim6reg%u" should not exceed 16 bytes (IFNAMSIZ) */
+		if (v != RT_TABLE_DEFAULT && v >= 100000000)
+			return -EINVAL;
 		if (sk == mrt->mroute6_sk)
 			return -EBUSY;