static bool netlink_filter_tap(const struct sk_buff *skb)
{
	struct sock *sk = skb->sk;

	/* We take the more conservative approach and
	 * whitelist socket protocols that may pass.
	 */
	switch (sk->sk_protocol) {
	case NETLINK_ROUTE:
	case NETLINK_USERSOCK:
	case NETLINK_SOCK_DIAG:
	case NETLINK_NFLOG:
	case NETLINK_XFRM:
	case NETLINK_FIB_LOOKUP:
	case NETLINK_NETFILTER:
	case NETLINK_GENERIC:
		return true;
	}

	return false;
}

The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations.