CVE-2026-70465

Unauthenticated DNS Buffer Overflow Enables Arbitrary Code Execution in FortiClientWindows

Published Aug 12, 2026 CVSS 3.1 · 7.3 High EPSS < 1% KEV · Not listed

Description

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.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Fortinet

FortiClientWindows

unaffected

Version	Status	Constraints
`7.4.0`	affected	≤ 7.4.3
`7.2.0`	affected	≤ 7.2.11

Configuration 1 [-]

OR	cpe:2.3:a:fortinet:forticlient::::::windows::*
	cpe:2.3:a:fortinet:forticlient::::::windows::*

No data.

Vendor Product Versions

Fortinet

Forticlientwindows

Version	Status	Scheme	Platform
`[7.4.0,7.4.3]`	affected	semver	—
`[7.2.0,7.2.11]`	affected	semver	—

Remediation

Vendor Solution

Upgrade to FortiClientWindows version 7.4.4 or above Upgrade to FortiClientWindows version 7.2.12 or above

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.516% probability within 30 days)

Exploitation none

Automatable no

Technical Impact total

References

Link	Providers
https://fortiguard.fortinet.com/psirt/FG-IR-26-156

History

Sep 8, 2026 9:15 PM First appearance in the feed. Affected versions updated. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Fortinet forticlient
CPEs		cpe:2.3:a:fortinet:forticlient::::::windows::*
Vendors & Products		Fortinet forticlient

Aug 13, 2026 1:30 AM Title updated View changes

Type	Values Removed	Values Added
Title		Unauthenticated DNS Buffer Overflow Enables Arbitrary Code Execution in FortiClientWindows

Aug 12, 2026 1:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Aug 12, 2026 12:15 PM Description updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		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.
First Time appeared		Fortinet Fortinet forticlientwindows
Weaknesses		CWE-120
CPEs		cpe:2.3:a:fortinet:forticlientwindows:7.2.0:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.10:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.11:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.1:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.2:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.3:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.4:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.5:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.6:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.7:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.8:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.2.9:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.4.0:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.4.1:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.4.2:::::::* cpe:2.3:a:fortinet:forticlientwindows:7.4.3:::::::*
Vendors & Products		Fortinet Fortinet forticlientwindows
References		https://fortiguard.fortinet.com/psirt/FG-IR-26-156
Metrics		cvssV3_1 `{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C'}`