Fortinet: Heap overflow in kernel driver due to missing size validation

Description

A buffer copy without checking size of input vulnerability [CWE-120] in FortiClient Windows may allow an unauthenticated attacker in a position to alter or craft DNS responses to the targeted host to execute arbitrary code via malicious packets. Revised on 2026-08-12 00:00:00

What to do

Install the fixed versions listed in the official advisory. If you cannot update right away, apply the workarounds or mitigations it describes and limit access to the affected service.

Details

Vendor

Fortinet

Product

FortiClient Windows

Affected versions

FortiClient Windows 7.4: from 7.4.0 to 7.4.3 — fixed in 7.4.4
FortiClient Windows 7.2: from 7.2.0 to 7.2.11 — fixed in 7.2.12 (from the advisory and NVD; check the exact builds in the official advisory)

CVSS score

7.3

Actively exploited

Not known at this time

Source

Fortinet PSIRT – original advisory

Published

August 12, 2026

The description and the recommended action are quoted from the public advisory (the action is our generic advice); severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.