Zennoxa Shield
Rules / C/C++
SHIELD-CPP-004

Use of gets is inherently unsafe

criticalC/C++CWE-242CVSS 9.8

What it detects

gets performs an unbounded read from stdin and always risks buffer overflow.

How to fix

Replace gets with fgets and a fixed buffer size.

Vulnerable — Shield flags thisinput.c
#include <stdio.h>

int main(void) {
    char name[64];
    gets(name);
    printf("Hello, %s\n", name);
    return 0;
}
Fixed — scans cleaninput.c
#include <stdio.h>

int main(void) {
    char name[64];
    if (fgets(name, sizeof(name), stdin) != NULL)
        printf("Hello, %s\n", name);
    return 0;
}

Both snippets are verified against the shipped scanner: the vulnerable one triggers SHIELD-CPP-004, the fixed one does not.

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SHIELD-CPP-004: Use of gets is inherently unsafe — Zennoxa Shield