The php_mysqlnd_read_error_from_line function in the Mysqlnd extension in PHP 5.3 through 5.3.2 does not properly calculate a buffer length, which allows context-dependent attackers to trigger a heap-based buffer overflow via crafted inputs that cause a negative length value to be used.
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.