Heap-based buffer overflow in the php_parserr function in ext/standard/dns.c in PHP 5.6.0beta4 and earlier allows remote servers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted DNS TXT record, related to the dns_get_record function.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.