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buffer overflow

A common cause of malfunctioning software. If the amount of data written into a buffer exceeds the size of the buffer, the additional data will be written into adjacent areas, which could be buffers, constants, flags or variables. Any aberrant behavior can result when control data, such as a binary flag, is altered erroneously (it only takes one bit!). Various instructions transfer data until a null or return or some other character signals the end of the data string. Such instructions are potentially dangerous and can be avoided by using instructions that read or transfer a precise number of bytes.

Malicious hackers can exploit buffer overflows by appending executable instructions to the end of data and causing that code to be run after it has entered memory (see Slammer). See buffer and buffer flush.

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(programming)

buffer overflow - What happens when you try to store more data in a buffer than it can handle. This may be due to a mismatch in the processing rates of the producing and consuming processes (see overrun and firehose syndrome), or because the buffer is simply too small to hold all the data that must accumulate before a piece of it can be processed. For example, in a text-processing tool that crunches a line at a time, a short line buffer can result in lossage as input from a long line overflows the buffer and overwrites data beyond it. Good defensive programming would check for overflow on each character and stop accepting data when the buffer is full. See also spam, overrun screw.