Cisco Secure Firewall Adaptive Security Appliance SSH Partial Private Key Authentication Bypass Vulnerability (Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software)

CVE-2026-20009
MEDIUM 5.3

At a glance

Source
NVD
EPSS
EPSS 0.44 % · percentile 38 ()
State
PUBLISHED
Published
Updated
Assigner
cisco
NVD status
Analyzed

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.  

Weaknesses (CWE)

  • CWE-138 — Improper Neutralization of Special Elements

References

Scores

VersionScoreVectorScored by
CVSS 3.1MEDIUM 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:Ncisco
CVSS 3.1MEDIUM 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NNVD · psirt@cisco.com (Secondary)

European references

Affected configurations (NVD CPE)

Affected products

ProductVersions
Cisco · Cisco Secure Firewall Adaptive Security Appliance (ASA) Softwareaffected 9.17.1 ; affected 9.17.1.7 ; affected 9.17.1.9 ; affected 9.17.1.10 ; affected 9.18.1 ; affected 9.18.1.3

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD