Detections
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Fortinet Fortigate 7.6.1 < 7.6.7 Improper Certificate Validation with Host Mismatch (FG-IR-26-174)

high Nessus Plugin ID 348166

Synopsis

Fortinet Firewall is missing one or more security-related updates.

Description

The version of Fortigate installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the FG-IR-26-174 advisory.

 - An improper validation of certificate with host mismatch vulnerability in Fortinet FortiOS 7.6.1 through 7.6.6 may allow attacker to information disclosure. (CVE-2026-84393)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to Fortigate (FortiOS) version 7.6.7 / 8.0.0 or later.

See Also

https://www.fortiguard.com/psirt/FG-IR-26-174

Plugin Details

Severity: High

ID: 348166

File Name: fortigate_FG-IR-26-174.nasl

Version: 1.1

Type: Local

Family: Firewalls

Published: 9/18/2026

Updated: 9/18/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.24

CVSS v2

Risk Factor: High

Base Score: 7.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-84393

CVSS v3

Risk Factor: High

Base Score: 8.1

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Vulnerability Information

CPE: cpe:/o:fortinet:fortios

Required KB Items: Host/Fortigate/model, Host/Fortigate/version

Patch Publication Date: 9/8/2026

Vulnerability Publication Date: 9/8/2026

Reference Information

CVE: CVE-2026-84393

IAVA: 2026-A-1004