SB2026111188 - Improper Authentication in FortiOS

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Main Vulnerability Database SB2026111188

SB2026111188 - Improper Authentication in FortiOS

Published: November 11, 2026

Security Bulletin ID SB2026111188
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper Authentication (CVE-ID: CVE-2026-121530)

CWE-ID: CWE-287 - Improper Authentication

CVSSv4: 7.5 [CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote privileged user to execute arbitrary code.

The vulnerability exists due to improper authentication in Two-Factor-Authentication. A remote authenticated attacker with at least read-only permission can log in to the FortiOS GUI with an invalid token after entering a valid username and password, in scenarios where the RADIUS server returns an additional "Access-Challenge" response following an invalid TFA token.


Remediation

Install update from vendor's website.

References