Monitor vulnerabilities like this one.
Sign up free to get alerted when software you use is affected.
5.3
Cisco ASA Firewall Software Allows Unauthorized SSH Access
CVE-2026-20009
Summary
A hacker can use a crafted SSH login attempt to gain unauthorized access to a Cisco ASA firewall device and execute commands as a specific user. This vulnerability exists because the device does not properly validate user input during the authentication process. To protect your device, ensure that you have the latest software updates installed and configure your SSH authentication settings securely.
Original title
A vulnerability in the implementation of the proprietary SSH stack with SSH key-based authentication in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software could allow an unauthenticat...
Original description
A vulnerability in the implementation of the proprietary SSH stack with SSH key-based authentication in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to log in to a Cisco Secure Firewall ASA device and execute commands as a specific user.
This vulnerability is due to insufficient validation of user input during the SSH authentication phase. An attacker could exploit this vulnerability by submitting crafted input during SSH authentication to an affected device. A successful exploit could allow the attacker to log in to the device as a specific user without the private SSH key of that user. To exploit this vulnerability, the attacker must possess a valid username and the associated public key. The private key is not required.
Notes:
Exploitation of this vulnerability does not provide the attacker with root access.
The authentication, authorization, and accounting (AAA) configuration command auto-enable is not affected by this vulnerability.
This vulnerability is due to insufficient validation of user input during the SSH authentication phase. An attacker could exploit this vulnerability by submitting crafted input during SSH authentication to an affected device. A successful exploit could allow the attacker to log in to the device as a specific user without the private SSH key of that user. To exploit this vulnerability, the attacker must possess a valid username and the associated public key. The private key is not required.
Notes:
Exploitation of this vulnerability does not provide the attacker with root access.
The authentication, authorization, and accounting (AAA) configuration command auto-enable is not affected by this vulnerability.
nvd CVSS3.1
5.3
Vulnerability type
CWE-138
Published: 4 Mar 2026 · Updated: 13 Mar 2026 · First seen: 6 Mar 2026