FortiClient <=7.4.3 DNS Buffer Overflow Vulnerability
CVE-2026-70465 Published on August 12, 2026
A buffer copy without checking size of input ('classic buffer overflow') vulnerability in Fortinet FortiClientWindows 7.4.0 through 7.4.3, FortiClientWindows 7.2.0 through 7.2.11 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.
Vulnerability Analysis
CVE-2026-70465 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Type
What is a Classic Buffer Overflow Vulnerability?
The program copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. A buffer overflow condition exists when a program attempts to put more data in a buffer than it can hold, or when a program attempts to put data in a memory area outside of the boundaries of a buffer. The simplest type of error, and the most common cause of buffer overflows, is the "classic" case in which the program copies the buffer without restricting how much is copied. Other variants exist, but the existence of a classic overflow strongly suggests that the programmer is not considering even the most basic of security protections.
CVE-2026-70465 has been classified to as a Classic Buffer Overflow vulnerability or weakness.
Products Associated with CVE-2026-70465
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Affected Versions
Fortinet FortiClientWindows:- Version 7.4.0, <= 7.4.3 is affected.
- Version 7.2.0, <= 7.2.11 is affected.