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 issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability none.
The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVE-2026-20009 is classified as CWE-138: Improper Neutralization of Special Elements. The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as control elements or syntactic markers when they are sent to a downstream component.
CVE-2026-20009 is recorded against 1 package.
Published on 4 March 2026 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.
adaptive-security-appliance-software has other advisories on record. If you are patching this one, these are worth checking on the same host:
These advisories are the same class of weakness (CWE-138: Improper Neutralization of Special Elements) in other software:
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| adaptive-security-appliance-software | 9.23.1 | 9.23.1.19 |
References
Similar Threats
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