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CVE-2026-126251Fortinet FortiAuthenticator incorrect authorization

High priorityCritical9.1EPSS not scored yet

CVE-2026-126251 is a incorrect authorization in Fortinet FortiAuthenticator, rated critical (9.1 on CVSS 3.1).

Why this priority: Critical, and reachable over the network without an account.

Published · Updated · NVD status: Received

What it is

A permission check exists but gets the answer wrong for some callers.

How it is reached

An attacker can exploit it over the network, without an account, and nobody has to click anything.

What an attacker gains

A successful attack can change data or behaviour and take it offline. In practice, this kind of flaw lets an attacker reach data or actions their role should not allow.

Is it being exploited?

There is no public report of exploitation yet.

What to do

  1. No fixed version is listed yet. Find every place Fortinet FortiAuthenticator runs, watch the references for a fix, and plan a replacement if it is no longer supported.
  2. While there is no fix, keep it off the internet or behind a VPN, allowlist or authenticating proxy.

Description from NVD

A incorrect authorization vulnerability in Fortinet FortiAuthenticator 8.0.0 through 8.0.3, FortiAuthenticator 6.6.0 through 6.6.10 may allow an attacker to bypass authentication and gain unauthorized access.

What this means for your architecture.

A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.

Components it touches

  • Network edge devices: VPNs, firewalls, routers and gateways. They sit between the internet and internal networks, so a flaw in one is often the first step into everything behind it.
  • Permission checks in APIs and admin surfaces. The flaw sits between one role or tenant and another.
  • Multi-tenant services. The flaw sits between one role or tenant and another.

Trust boundaries in play

  • Internet-facing entry points. No account is needed. Any instance reachable from outside your perimeter, through a load balancer, gateway, VPN or exposed admin port, is in scope.
  • Between one role or tenant and another. An attacker who crosses it can reach data or actions their role should not allow.

Questions to answer about your own systems

  • Where does Fortinet FortiAuthenticator run in your systems, and at which version?
  • Which of those instances can be reached from the internet or partner networks?
  • What can it reach once compromised: which data stores, secrets and services?

Sources

  • CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
  • Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
  • Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
  • Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.