--- a/netwerk/dns/mdns/libmdns/MDNSResponderReply.cpp
+++ b/netwerk/dns/mdns/libmdns/MDNSResponderReply.cpp
@@ -276,17 +276,21 @@ GetAddrInfoReplyRunnable::Reply(DNSServi
   }
 
   nsCOMPtr<nsIThread> thread(obj->GetThread());
   if (!thread) {
     return;
   }
 
   NetAddr address;
-  memcpy(&address, aAddress, sizeof(*aAddress));
+  address.raw.family = aAddress->sa_family;
+
+  static_assert(sizeof(address.raw.data) >= sizeof(aAddress->sa_data),
+                "size of sockaddr.sa_data is too big");
+  memcpy(&address.raw.data, aAddress->sa_data, sizeof(aAddress->sa_data));
 
   thread->Dispatch(new GetAddrInfoReplyRunnable(aSdRef,
                                                 aFlags,
                                                 aInterfaceIndex,
                                                 aErrorCode,
                                                 nsCString(aHostName),
                                                 address,
                                                 aTTL,