CWE 788

The software reads or writes to a buffer using an index or pointer that references a memory location after the end of the buffer.

This typically occurs when a pointer or its index is decremented to a position before the buffer, when pointer arithmetic results in a position before the beginning of the valid memory location, or when a negative index is used. These problems may be resultant from missing sentinel values (CWE-463) or trusting a user-influenced input length variable.