A critical vulnerability (CVE-2024-21762) has been discovered in Fortinet's FortiOS and FortiProxy products. The vulnerability specifically exists in FortiOS versions 7.4. to 7.4.2, 7.2. to 7.2.6, 7.. to 7..13, 6.4. to 6.4.14, 6.2. to 6.2.15, 6.. to 6..17 and FortiProxy versions 7.4. to 7.4.2, 7.2. to 7.2.8, 7.. to 7..14, 2.. to 2..13, 1.2. to 1.2.13, 1.1. to 1.1.6, 1.. to 1..7. Attackers can exploit this vulnerability to execute unauthorized code or commands on the affected devices via specifically crafted requests.

Understanding CVE-2024-21762

To exploit this vulnerability, an attacker would send specifically crafted requests to the affected devices. The malicious requests would trigger an out-of-bounds write, leading to potential arbitrary code execution or command execution without proper authorization.

Exploit Details

The vulnerability results from insufficient input validation and boundary checks when processing certain requests. Here's an example of a code snippet that demonstrates this vulnerability:

// Vulnerable code snippet
char buffer[1024];

void vulnerable_function(char *input) {
  int len = strlen(input);
  for (int i = ; i < len; i++) {
  buffer[i] = input[i];

In the above code snippet, the input received is not validated or boundary-checked, leading to a potential buffer overflow and out-of-bounds write when the input length is greater than the buffer size.


Fortinet has released patches for the affected versions of FortiOS and FortiProxy. Users are strongly recommended to update their devices to the latest patched versions. The patch release notes and upgrade instructions from Fortinet can be found at the following links:

- FortiOS Patch Notes: FortiOS Release Notes
- FortiProxy Patch Notes: FortiProxy Release Notes

In addition to patching the devices, users can implement the following security best practices to reduce the risk of exploitation:

Use network segmentation to limit the possible attack surface.

3. Employ strong authentication and access control mechanisms for user accounts and device management interfaces.
4. Monitor and filter outbound network traffic from the devices to detect and block any unauthorized communication.


CVE-2024-21762 is a critical out-of-bounds write vulnerability affecting several versions of Fortinet's FortiOS and FortiProxy products. Organizations using the affected products should apply the patches immediately and implement security best practices to protect their systems from potential exploitation.


Published on: 02/09/2024 09:15:08 UTC
Last modified on: 02/10/2024 02:00:01 UTC