FG-IR-26-267: Authentication bypass by primary weakness

Published Nov 10, 2026

Updated

An Authentication Bypass by Primary Weakness vulnerability [cwe-305] in FortiOS and FortiSASE ospf daemon may allow an unauthenticated attacker to broadcast LSA via specially crafted request

Affected Software

12 affected componentsFixes available

Fortinet FortiOS>=8.0.0<=8.0.1

Fortinet FortiOS>=7.6.0<=7.6.7

Fortinet FortiOS>=7.4.0<=7.4.12

Fortinet FortiOS>=7.2.0<=7.2.13

Fortinet FortiSASE=6

Fortinet FortiSASE>=26.2

Fortinet FortiSASE>=26.1

Fortinet FortiSASE>=25.4

Fortinet FortiSASE>=25.3

Fortinet FortiSASE>=25.2

Fortinet FortiSASE 25.1.a=5

Fortinet FortiSASE>=25.1

Event History

Nov 10, 2026

Advisory Published

via FortiGuard·12:00 AM

Data Sourced

via FortiGuard·12:00 AM

DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

What level of network access does an attacker need?

The attack vector is adjacent network access. The attacker must be able to send specially crafted requests to the OSPF daemon and does not need prior authentication or user interaction.

What is the expected security impact?

The vulnerability can allow broadcast of LSA messages, with high integrity and availability impact. The provided vector indicates no confidentiality impact.

Which systems should be prioritized for review?

FortiOS and FortiSASE deployments running the OSPF daemon should be reviewed, including FortiSASE 25.1.a as listed in the affected software information.

FG-IR-26-267: Authentication bypass by primary weakness

Affected Software

Event History

Frequently Asked Questions

What level of network access does an attacker need?

What is the expected security impact?

Which systems should be prioritized for review?

Company

Resources

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Frequently Asked Questions

What level of network access does an attacker need?

What is the expected security impact?

Which systems should be prioritized for review?