--- src/rfc1035.c.orig
+++ src/rfc1035.c
@@ -1624,6 +1624,9 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
   int rd_bit = (header->hb3 & HB3_RD);
   int count = 255; /* catch loops */
 
+  // Make sure we do not underflow here too.
+  if ((ssize_t)qlen > (limit - ((char *)header))) return 0;
+
   /* Suppress cached answers if no_cache set. */
   if (no_cache)
     rd_bit = 0;