Fortinet FortiWeb Broken access control in the RADIUS type admin group (FG-IR-26-158)

critical Nessus Plugin ID 337247

Synopsis

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

Description

The version of FortiWeb installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the FG-IR-26-158 advisory.

- An Improper Authentication vulnerability [CWE-287] vulnerability in Fortinet FortiWeb 8.0.0 through 8.0.2, FortiWeb 7.6.0 through 7.6.6, FortiWeb 7.4.0 through 7.4.11, FortiWeb 7.2.0 through 7.2.12, FortiWeb 7.0.0 through 7.0.12 may allow a remote unauthenticated attacker to login into the Fortiweb GUI/CLI with a random username and password (CVE-2026-26035)

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

Solution

For 7.2.x, upgrade to FortiWeb version 7.2.13 or later. For 7.4.x, upgrade to FortiWeb version 7.4.12 or later. For 7.6.x, upgrade to FortiWeb version 7.6.7 or later. For 8.0.x, upgrade to FortiWeb version 8.0.3 or later.

Plugin Details

Severity: Critical

ID: 337247

File Name: fortiweb_FG-IR-26-158.nasl

Version: 1.1

Type: Local

Family: Firewalls

Published: 8/18/2026

Updated: 8/18/2026

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.13

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-26035

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:fortinet:fortiweb

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

Exploit Ease: No known exploits are available

Patch Publication Date: 8/12/2026

Vulnerability Publication Date: 8/12/2026

Reference Information

CVE: CVE-2026-26035

Detections

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