diff --git a/net/bridge/netfilter/ebt_snat.c b/net/bridge/netfilter/ebt_snat.c
index 7dfbcdfc30e5d22dfac17ee01db590a5abe13e70..c9e229af0366b8659fb56c41ef36e2e05268ddb6 100644
--- a/net/bridge/netfilter/ebt_snat.c
+++ b/net/bridge/netfilter/ebt_snat.c
@@ -31,6 +31,9 @@ ebt_snat_tg(struct sk_buff *skb, const struct xt_action_param *par)
 		const struct arphdr *ap;
 		struct arphdr _ah;
 
+		if (skb_ensure_writable(skb, sizeof(_ah) + ETH_ALEN))
+			return EBT_DROP;
+
 		ap = skb_header_pointer(skb, 0, sizeof(_ah), &_ah);
 		if (ap == NULL)
 			return EBT_DROP;