How can a stack buffer overrun occur in C/C++?

In C/C++, stack buffer overruns commonly occur due to unchecked string manipulation functions like `strcpy`, `strcat`, `gets`, and `sprintf`. If the source string is larger than the destination buffer, these functions will write past the end of the buffer. Also, recursive functions without proper base cases can exhaust the stack space, leading to similar issues. Incorrect array indexing can also cause this.