CVE-2026-20017
📋 TL;DR
This vulnerability allows authenticated local attackers with administrative credentials on Cisco Secure FTD devices to execute arbitrary commands as root via command injection in the CLI. It affects Cisco Secure FTD Software due to insufficient input validation of command arguments.
💻 Affected Systems
- Cisco Secure Firewall Threat Defense (FTD)
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the firewall device, allowing root-level command execution, lateral movement to connected networks, and persistent backdoor installation.
Likely Case
Privilege escalation from administrative user to root, enabling configuration changes, data exfiltration, or disabling security controls.
If Mitigated
Limited impact if administrative access is tightly controlled and monitored, though root access could still be obtained.
🎯 Exploit Status
Exploitation requires authenticated administrative access and knowledge of vulnerable CLI commands
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Cisco advisory for specific fixed versions
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-cmd-inj-mTzGZexf
Restart Required: Yes
Instructions:
1. Review Cisco advisory for affected versions. 2. Download and apply appropriate patch from Cisco. 3. Restart affected FTD devices. 4. Verify patch installation.
🔧 Temporary Workarounds
Restrict Administrative Access
allLimit administrative CLI access to trusted users and networks only
Monitor Administrative Sessions
allImplement session logging and monitoring for all administrative CLI access
🧯 If You Can't Patch
- Implement strict access controls for administrative accounts
- Enable detailed logging and monitoring of all CLI commands executed
🔍 How to Verify
Check if Vulnerable:
Check Cisco advisory for affected versions and compare with your FTD versionCheck Version:
show version (in FTD CLI)Verify Fix Applied:
Verify FTD software version matches or exceeds patched version from Cisco advisory📡 Detection & Monitoring
Log Indicators:
- Unusual CLI command patterns
- Multiple failed authentication attempts followed by successful admin login
- Commands with unusual arguments or shell metacharacters
Network Indicators:
- Unexpected outbound connections from FTD management interface
- Changes to firewall rules without proper change control
SIEM Query:
source="ftd_cli_logs" AND (command="*;*" OR command="*|*" OR command="*`*" OR command="*$(*")