John works as a C programmer. He develops the following C program:

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
int buffer(char *str) {
char buffer1[10];
strcpy(buffer1, str);
return 1;
}
int main(int argc, char *argv[]) {
buffer (argv[1]);
printf("Executed\n");
return 1;
}
His program is vulnerable to a __________ attack.