CVE-2026-22628: FortiSwitchAXFixed Auth Bypass Vulnerability

CVE-2026-22628 Overview

An improper access control vulnerability exists in Fortinet FortiSwitchAXFixed versions 1.0.0 through 1.0.1. This security flaw may allow an authenticated administrator to execute arbitrary system commands through a specifically crafted SSH configuration file. While the vulnerability requires authenticated admin access, it poses a significant risk as it enables command execution beyond the intended administrative capabilities.

Critical Impact

Authenticated administrators can leverage malicious SSH configuration files to execute arbitrary system commands, potentially compromising the integrity, confidentiality, and availability of the affected FortiSwitchAXFixed devices.

Affected Products

• Fortinet FortiSwitchAXFixed version 1.0.0
• Fortinet FortiSwitchAXFixed version 1.0.1

Discovery Timeline

• 2026-03-10 - CVE-2026-22628 published to NVD
• 2026-03-11 - Last updated in NVD database

Technical Details for CVE-2026-22628

Vulnerability Analysis

This vulnerability falls under CWE-284 (Improper Access Control), indicating that the application fails to properly restrict access to a resource or functionality. In this case, the FortiSwitchAXFixed system does not adequately validate or sanitize SSH configuration files processed by authenticated administrators.

The local attack vector requires an attacker to have existing administrative access to the device. While this limits the initial attack surface, administrators with malicious intent or compromised admin credentials could leverage this vulnerability to execute commands that should be outside the scope of normal administrative operations. The impact affects confidentiality, integrity, and availability of the system, allowing potential data exfiltration, system modification, or service disruption.

Root Cause

The root cause stems from insufficient input validation and access control enforcement when processing SSH configuration files. The system trusts administrator-supplied configuration data without properly sanitizing or restricting command execution capabilities embedded within the SSH config file structure. This allows specially crafted configuration directives to break out of the expected parsing context and execute arbitrary system commands.

Attack Vector

The attack requires local access with administrative privileges to the FortiSwitchAXFixed device. An attacker must craft a malicious SSH configuration file containing embedded command sequences and then upload or apply this configuration through the administrative interface. When the system processes this malicious configuration, the embedded commands are executed with elevated privileges.

The attack flow involves:

1. Gaining authenticated administrative access to the FortiSwitchAXFixed device
2. Crafting a malicious SSH configuration file with embedded command injection payloads
3. Uploading or applying the malicious configuration through the admin interface
4. System processes the configuration and executes the embedded commands

For technical details on the vulnerability mechanism, refer to the Fortinet PSIRT Advisory FG-IR-26-085.

Detection Methods for CVE-2026-22628

Indicators of Compromise

• Unexpected or unauthorized modifications to SSH configuration files on FortiSwitchAXFixed devices
• Unusual command execution logs or system activity following SSH configuration changes
• Administrative sessions making atypical configuration modifications
• Evidence of privilege escalation or lateral movement originating from FortiSwitchAXFixed devices

Detection Strategies

• Monitor and audit all SSH configuration file changes on affected FortiSwitchAXFixed devices
• Implement file integrity monitoring for SSH-related configuration directories
• Review administrative access logs for unusual patterns or unauthorized access attempts
• Deploy behavioral analysis to detect anomalous command execution patterns

Monitoring Recommendations

• Enable comprehensive logging for all administrative actions on FortiSwitchAXFixed devices
• Implement real-time alerting for SSH configuration modifications
• Regularly audit administrator accounts and access permissions
• Correlate FortiSwitchAXFixed logs with SIEM platforms for broader threat visibility

How to Mitigate CVE-2026-22628

Immediate Actions Required

• Review and restrict administrative access to FortiSwitchAXFixed devices to only essential personnel
• Audit current SSH configuration files for any suspicious or unexpected content
• Implement additional monitoring on affected systems until patches can be applied
• Consider network segmentation to limit exposure of vulnerable devices

Patch Information

Fortinet has addressed this vulnerability in their security advisory. Administrators should consult the Fortinet PSIRT Advisory FG-IR-26-085 for official patch information and upgrade instructions. Updating to a patched version of FortiSwitchAXFixed is the recommended remediation approach.

Workarounds

• Implement strict administrative access controls and limit the number of admin accounts
• Enable multi-factor authentication for all administrative access
• Review and harden SSH configuration handling through available security features
• Deploy network access controls to restrict administrative interface access to trusted networks only

# Configuration example - Restrict administrative access
# Limit admin access to specific trusted IP addresses
config system admin
    edit "admin"
        set trusthost1 10.0.0.0 255.255.255.0
        set trusthost2 192.168.1.0 255.255.255.0
    next
end