An exploit is the use of a bug or glitch by a player to their advantage in a manner not intended by the game's designers; however, the precise determination of what is or is not considered an exploit can be controversial. This debate stems from a number of factors but typically involves the argument that the issues are part of the game and require no changes or external programs to take advantage of them.
Glitches are errors in the code, most commonly associated with unintended actions rather than crashes and other game issues. Errors in the code that prevent the game from functioning properly are often referred to as bugs. Exploits are methods of taking advantage of glitches to gain an unfair advantage over other players.