CVE-2025-46776
📋 TL;DR
This CVE describes a classic buffer overflow vulnerability in Fortinet FortiExtender devices that allows authenticated users to execute arbitrary code or commands via crafted CLI commands. The vulnerability affects multiple FortiExtender versions from 7.0 through 7.6.1. Attackers with authenticated access can potentially gain full control of affected devices.
💻 Affected Systems
- Fortinet FortiExtender
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
An authenticated attacker gains remote code execution with root privileges, leading to complete device compromise, lateral movement into connected networks, and persistent backdoor installation.
Likely Case
Authenticated users (including compromised accounts) execute arbitrary commands to disrupt services, steal configuration data, or pivot to other network segments.
If Mitigated
With proper access controls and network segmentation, impact is limited to the FortiExtender device itself without lateral movement.
🎯 Exploit Status
Exploitation requires authenticated access to CLI; buffer overflow exploitation requires specific knowledge of memory layout.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FortiExtender 7.6.2, 7.4.7, and later versions
Vendor Advisory: https://fortiguard.fortinet.com/psirt/FG-IR-25-251
Restart Required: Yes
Instructions:
1. Download the patched firmware from Fortinet support portal. 2. Backup current configuration. 3. Upload and install the new firmware via web interface or CLI. 4. Reboot the device. 5. Verify the new version is running.
🔧 Temporary Workarounds
Restrict CLI Access
allLimit CLI access to trusted administrative accounts only and implement strong authentication.
config system admin
edit <admin_user>
set accprofile "super_admin"
set password <strong_password>
end
Network Segmentation
allIsolate FortiExtender devices in separate network segments with strict firewall rules.
🧯 If You Can't Patch
- Implement strict access controls to limit CLI access to essential personnel only
- Monitor and audit all CLI commands executed on FortiExtender devices
🔍 How to Verify
Check if Vulnerable:
Check FortiExtender firmware version via web interface or CLI command 'get system status'Check Version:
get system status | grep VersionVerify Fix Applied:
Verify firmware version is 7.6.2, 7.4.7, or later after patching📡 Detection & Monitoring
Log Indicators:
- Unusual CLI command patterns
- Multiple failed authentication attempts followed by successful login
- Execution of unexpected system commands
Network Indicators:
- Unusual outbound connections from FortiExtender devices
- Traffic patterns inconsistent with normal operations
SIEM Query:
source="fortiextender" AND (event_type="cli_command" AND command="*" | stats count by user, command)