Buffer overflow in the mysql_real_connect function in MySQL 4.x before 4.0.21, and 3.x before 3.23.49, allows remote DNS servers to cause a denial of service and possibly execute arbitrary code via a DNS response with a large address length (h_length).
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.