CVE-2026-20008: Medium Vulnerability in Cisco Adaptive Security Appliance Software

A vulnerability in a small subset of CLI commands that are used on Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, local attacker to craft Lua code that could be used on the underlying operating system as root. This vulnerability exists because user-provided input is not properly sanitized. An attacker could exploit this vulnerability by crafting valid Lua code and submitting it as a malicious parameter for a CLI command. A successful exploit could allow the attacker to inject Lua code, which could lead to arbitrary code execution as the root user. To exploit this vulnerability, an attacker must have valid Administrator credentials.

The severity level of this vulnerability is classified as medium, with a CVSS score of 6. This score indicates a moderate risk to organizations utilizing the affected Cisco products. The potential for exploitation emphasizes the need for organizations to be vigilant.

Risk to organizations includes the possibility of unauthorized access and control over critical system functionalities. Attackers may leverage this vulnerability to execute arbitrary code, potentially leading to significant operational disruptions and data breaches.

Organizations should prioritize patching immediately. The exploitation status is currently listed as not known to be actively exploited or associated with public exploits, which provides a window for remediation efforts.

In light of these factors, immediate action is necessary to mitigate the risks associated with this vulnerability.

Vulnerability Details

This vulnerability allows an authenticated local attacker to execute Lua code as the root user on Cisco Secure Firewall ASA and FTD Software. It is categorized under CWE-78, which pertains to OS Command Injection. The vulnerability was published on March 4, 2026, and affects specific versions of both ASA and FTD software.

Technical Analysis

The root cause of this vulnerability is the insufficient sanitization of user input, allowing an attacker to inject malicious Lua code via CLI commands. The attack vector is local, requiring high privileges (Administrator credentials) to execute the exploit. The attack complexity is low, meaning that an attacker with the necessary credentials can exploit this vulnerability without significant effort. The potential impacts include high confidentiality and integrity loss, while availability remains unaffected.

Risk & Impact Analysis

Organizations deploying Cisco Secure Firewall ASA and FTD Software should recognize the substantial risk posed by this vulnerability. The ability for an attacker to execute arbitrary code as root can compromise the confidentiality and integrity of sensitive data and systems. The urgency of the threat is underscored by the potential for operational disruptions and data breaches. Given the CVSS score of 6, this vulnerability should be addressed in the priority patch cycle.

Exploitation Status

Affected Versions

The affected versions of Cisco Secure Firewall ASA Software include 9.12.1 to 9.16.4.85, 9.17.1 to 9.18.4.66, 9.19.1 to 9.20.4, 9.22.1.1 to 9.22.2.4, and 9.23.1 to 9.23.1.7. For Cisco Secure Firewall FTD Software, affected versions range from 6.4.0 to 7.0.9, 7.1.0 to 7.2.11, 7.3.0 to 7.4.3, 7.6.0 to 7.6.4, and 7.7.0 to 7.7.11.

Mitigation & Remediation

Organizations should implement the necessary patches to remediate this vulnerability. Specific updates and configurations can be found in the vendor advisory. In case a patch is unavailable, organizations are encouraged to implement configuration hardening and network controls to mitigate exposure. Continuous monitoring for suspicious activities is also recommended. For further guidance, organizations can refer to the application security assessment resources that provide additional remediation strategies.

Detection Guidance

To detect potential exploitation attempts, organizations should monitor logs for unusual CLI command usage and Lua script execution. Behavioral anomalies such as unauthorized access attempts or privilege escalations should be flagged for further investigation. Additionally, network signatures indicative of such activities should be implemented.

AppSecure Threat Intelligence Insight

The long-term significance of this vulnerability highlights the importance of input validation in software development. As organizations increasingly adopt automated tools and scripts, the risk of similar vulnerabilities will grow unless proactive measures are taken. This incident serves as a reminder for security teams to prioritize secure coding practices and regular vulnerability assessments. To stay informed about the latest trends in vulnerability management, organizations can explore the vulnerability management program and consider implementing comprehensive penetration testing methodologies to enhance their security posture.

Known Exploitation Timeline

As of now, this vulnerability is not included in the Known Exploited Vulnerabilities (KEV) catalog, indicating that it has not been actively exploited in the wild.

EPSS Risk Context

The EPSS score for this vulnerability is 0.00031, placing it in the 0.08794 percentile. This indicates a low likelihood of exploitation in the near term, but organizations should remain vigilant.