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TI-2026-16228 Aliases CVE-2026-20009GHSA-fqfv-4r6p-w7m3

Cisco Secure Firewall Adaptive Security Appliance SSH Partial Private Key Authentication Bypass Vulnerability

Priority LOW 30CWE-138Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · None · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

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.  

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00442 38th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
CiscoCisco Secure Firewall Adaptive Security Appliance (ASA) Software9.17.1; 9.17.1.7; 9.17.1.9; 9.17.1.10; 9.18.1; 9.18.1.3; 9.17.1.11; 9.18.2; 9.17.1.13; 9.17.1.15; 9.18.2.5; 9.17.1.20; 9.18.2.7; 9.19.1; 9.18.2.8; 9.18.3; 9.19.1.5; 9.17.1.30; 9.19.1.9; 9.18.3.39; 9.19.1.12; 9.18.3.46; 9.19.1.18; 9.18.3.53; 9.18.3.55; 9.17.1.33; 9.18.3.56; 9.20.1; 9.19.1.22; 9.18.4; 9.20.1.5; 9.18.4.5; 9.19.1.24; 9.18.4.8; 9.20.2; 9.19.1.27; 9.18.4.22; 9.20.2.10; 9.19.1.28; 9.17.1.39; 9.18.4.24; 9.20.2.21; 9.19.1.31; 9.18.4.29; 9.20.2.22; 9.18.4.34; 9.20.3; 9.18.4.40; 9.23.1; 9.22.1.1; 9.20.3.4; 9.18.4.47; 9.20.3.7; 9.17.1.45; 9.19.1.37; 9.17.1.46; 9.20.3.9; 9.19.1.38; 9.18.4.50; 9.22.1.3; 9.20.3.10; 9.22.1.2; 9.18.4.52; 9.20.3.13; 9.22.1.6; 9.18.4.53; 9.22.2; 9.20.3.16; 9.19.1.42; 9.18.4.57; 9.23.1.3; 9.20.3.20; 9.22.2.4; 9.23.1.7; 9.20.4; 9.22.2.9; 9.23.1.13; 9.20.4.7; 9.22.2.13; 9.18.4.66; 9.18.4.67; 9.18.4.68—No fix listedCNA
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software VendorCisco Affected 9.17.1; 9.17.1.7; 9.17.1.9; 9.17.1.10; 9.18.1; 9.18.1.3; 9.17.1.11; 9.18.2; 9.17.1.13; 9.17.1.15; 9.18.2.5; 9.17.1.20; 9.18.2.7; 9.19.1; 9.18.2.8; 9.18.3; 9.19.1.5; 9.17.1.30; 9.19.1.9; 9.18.3.39; 9.19.1.12; 9.18.3.46; 9.19.1.18; 9.18.3.53; 9.18.3.55; 9.17.1.33; 9.18.3.56; 9.20.1; 9.19.1.22; 9.18.4; 9.20.1.5; 9.18.4.5; 9.19.1.24; 9.18.4.8; 9.20.2; 9.19.1.27; 9.18.4.22; 9.20.2.10; 9.19.1.28; 9.17.1.39; 9.18.4.24; 9.20.2.21; 9.19.1.31; 9.18.4.29; 9.20.2.22; 9.18.4.34; 9.20.3; 9.18.4.40; 9.23.1; 9.22.1.1; 9.20.3.4; 9.18.4.47; 9.20.3.7; 9.17.1.45; 9.19.1.37; 9.17.1.46; 9.20.3.9; 9.19.1.38; 9.18.4.50; 9.22.1.3; 9.20.3.10; 9.22.1.2; 9.18.4.52; 9.20.3.13; 9.22.1.6; 9.18.4.53; 9.22.2; 9.20.3.16; 9.19.1.42; 9.18.4.57; 9.23.1.3; 9.20.3.20; 9.22.2.4; 9.23.1.7; 9.20.4; 9.22.2.9; 9.23.1.13; 9.20.4.7; 9.22.2.13; 9.18.4.66; 9.18.4.67; 9.18.4.68 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*9.17.1 to before 9.18.4.71; 9.19.1 to before 9.20.4.10; 9.22.1.1 to before 9.22.2.14; 9.23.1 to before 9.23.1.19VulnerableCisco
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* Versions 9.17.1 to before 9.18.4.71; 9.19.1 to before 9.20.4.10; 9.22.1.1 to before 9.22.2.14; 9.23.1 to before 9.23.1.19 Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-20009
  2. 2026-10-03 Alias added: GHSA-fqfv-4r6p-w7m3

References

Advisory 1

  • TI-2025-14628 Buffer overflow in Cisco Secure Firewall Adaptive Security Appliance Software KEVCVSS 3.1CRITICAL 9.9
  • TI-2016-05454 Buffer overflow in Cisco Adaptive Security Appliance (ASA) Software through 9.4.2.3 on… KEVCVSS 3.1HIGH 8.8
  • TI-2023-06973 Authentication bypass in Cisco Adaptive Security Appliance Software KEVCVSS 3.1CRITICAL 9.1
  • TI-2026-82192 Denial of service in Cisco Secure Firewall ASA and FTD SSL VPN KEVCVSS 3.1HIGH 8.6
  • TI-2026-16533 Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense… KEVCVSS 3.1HIGH 8.6
  • TI-2025-14657 Missing authorization in Cisco Secure Firewall Adaptive Security Appliance Software KEVCVSS 3.1HIGH 8.6
See all 354 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences