Daily security quiz #3

Question for 2026-11-03. Read the code and pick the most serious security vulnerability.

This function takes a user name and prints a greeting. What is the most serious vulnerability?

1#include <stdio.h>
2#include <string.h>
3 
4void greet(const char *name) {
5    char buf[32];
6    strcpy(buf, "Hello, ");
7    strcat(buf, name);
8    printf("%s\n", buf);
9}

1. AA format string is passed directly to printf, allowing a format string attack
2. Bbuf is not initialised to 0, causing information disclosure
3. CThe length of name is not checked, causing a buffer overflow that writes past buf
4. DIt takes a const char *, so name cannot be modified