CVE-2026-20008
📋 TL;DR
This vulnerability allows authenticated local attackers with Administrator credentials to execute arbitrary code as root on Cisco ASA and FTD devices by injecting malicious Lua code through specific CLI commands. It affects Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software. The root cause is improper input sanitization of user-provided Lua code.
💻 Affected Systems
- Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
- Cisco Secure Firewall Threat Defense (FTD) Software
⚠️ 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 system compromise with root-level arbitrary code execution, allowing attacker to install persistent backdoors, exfiltrate sensitive data, or disrupt firewall operations.
Likely Case
Privilege escalation from authenticated Administrator to root-level access, enabling lateral movement within the network or modification of firewall rules.
If Mitigated
No impact if proper access controls prevent unauthorized Administrator access and input validation is implemented.
🎯 Exploit Status
Exploitation requires valid Administrator credentials and knowledge of specific 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-asaftd-luainject-VescqgmS
Restart Required: Yes
Instructions:
1. Review Cisco advisory for affected versions. 2. Download and apply appropriate patch from Cisco Software Center. 3. Reboot device after patch installation. 4. Verify patch installation with version check.
🔧 Temporary Workarounds
Restrict Administrator Access
allLimit Administrator account access to only trusted personnel and implement multi-factor authentication.
Monitor CLI Command Usage
allImplement logging and monitoring for CLI commands that accept Lua code parameters.
🧯 If You Can't Patch
- Implement strict access controls for Administrator accounts and monitor for suspicious activity.
- Disable or restrict usage of CLI commands that accept Lua code if not required for operations.
🔍 How to Verify
Check if Vulnerable:
Check device version against affected versions listed in Cisco advisory. Review if vulnerable CLI commands accepting Lua code are enabled.Check Version:
show version (on Cisco ASA/FTD CLI)Verify Fix Applied:
Verify installed software version matches or exceeds patched version from Cisco advisory. Test if Lua code injection is no longer possible.📡 Detection & Monitoring
Log Indicators:
- Unusual CLI command usage with Lua code parameters
- Multiple failed authentication attempts followed by successful Administrator login
- Unexpected system modifications or file changes
Network Indicators:
- Unusual outbound connections from firewall device
- Anomalous traffic patterns through firewall
SIEM Query:
source="cisco_asa" AND (command="*lua*" OR command="*script*")