Product:
Cisco Secure Firewall Adaptive Security Appliance
Summary
A vulnerability in the implementation of the proprietary SSH stack with SSH key-based authentication could allow an unauthenticated, remote attacker to log in to a device and execute commands as a specific user. This is due to insufficient validation of user input during the SSH authentication phase. An attacker could exploit this by submitting crafted input during SSH authentication to gain access without the private SSH key.
Details
| Severity | Base Score | CVE |
|---|---|---|
| MEDIUM | 5.3 | CVE-2026-20009 |
Exploitation
To exploit this vulnerability, an attacker must possess a valid username and the associated public key. By submitting crafted input during the SSH authentication phase, the attacker can log in to the device as a specific user without needing the private key. It is important to note that exploitation does not grant root access to the attacker.
Affected Products
- Cisco Secure Firewall ASA Software: Vulnerable due to insufficient validation of user input during SSH authentication.
Mitigation
To mitigate this vulnerability, it is recommended to implement strict input validation and ensure that SSH key-based authentication is configured securely. Regularly updating the device software and monitoring for unauthorized access attempts can also help reduce the risk of exploitation.