FKIE_CVE-2026-20009
Vulnerability from fkie_nvd - Published: 2026-03-04 18:16 - Updated: 2026-06-17 10:16
Severity
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.
References
Impacted products
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unknown",
"product": "Cisco Secure Firewall Adaptive Security Appliance (ASA) Software",
"vendor": "Cisco",
"versions": [
{
"status": "affected",
"version": "9.17.1"
},
{
"status": "affected",
"version": "9.17.1.7"
},
{
"status": "affected",
"version": "9.17.1.9"
},
{
"status": "affected",
"version": "9.17.1.10"
},
{
"status": "affected",
"version": "9.18.1"
},
{
"status": "affected",
"version": "9.18.1.3"
},
{
"status": "affected",
"version": "9.17.1.11"
},
{
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"version": "9.18.2"
},
{
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"version": "9.17.1.13"
},
{
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"version": "9.17.1.15"
},
{
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"version": "9.18.2.5"
},
{
"status": "affected",
"version": "9.17.1.20"
},
{
"status": "affected",
"version": "9.18.2.7"
},
{
"status": "affected",
"version": "9.19.1"
},
{
"status": "affected",
"version": "9.18.2.8"
},
{
"status": "affected",
"version": "9.18.3"
},
{
"status": "affected",
"version": "9.19.1.5"
},
{
"status": "affected",
"version": "9.17.1.30"
},
{
"status": "affected",
"version": "9.19.1.9"
},
{
"status": "affected",
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},
{
"status": "affected",
"version": "9.19.1.12"
},
{
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},
{
"status": "affected",
"version": "9.19.1.18"
},
{
"status": "affected",
"version": "9.18.3.53"
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{
"status": "affected",
"version": "9.18.3.55"
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{
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{
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{
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{
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{
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{
"status": "affected",
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{
"status": "affected",
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{
"status": "affected",
"version": "9.19.1.27"
},
{
"status": "affected",
"version": "9.18.4.22"
},
{
"status": "affected",
"version": "9.20.2.10"
},
{
"status": "affected",
"version": "9.19.1.28"
},
{
"status": "affected",
"version": "9.17.1.39"
},
{
"status": "affected",
"version": "9.18.4.24"
},
{
"status": "affected",
"version": "9.20.2.21"
},
{
"status": "affected",
"version": "9.19.1.31"
},
{
"status": "affected",
"version": "9.18.4.29"
},
{
"status": "affected",
"version": "9.20.2.22"
},
{
"status": "affected",
"version": "9.18.4.34"
},
{
"status": "affected",
"version": "9.20.3"
},
{
"status": "affected",
"version": "9.18.4.40"
},
{
"status": "affected",
"version": "9.23.1"
},
{
"status": "affected",
"version": "9.22.1.1"
},
{
"status": "affected",
"version": "9.20.3.4"
},
{
"status": "affected",
"version": "9.18.4.47"
},
{
"status": "affected",
"version": "9.20.3.7"
},
{
"status": "affected",
"version": "9.17.1.45"
},
{
"status": "affected",
"version": "9.19.1.37"
},
{
"status": "affected",
"version": "9.17.1.46"
},
{
"status": "affected",
"version": "9.20.3.9"
},
{
"status": "affected",
"version": "9.19.1.38"
},
{
"status": "affected",
"version": "9.18.4.50"
},
{
"status": "affected",
"version": "9.22.1.3"
},
{
"status": "affected",
"version": "9.20.3.10"
},
{
"status": "affected",
"version": "9.22.1.2"
},
{
"status": "affected",
"version": "9.18.4.52"
},
{
"status": "affected",
"version": "9.20.3.13"
},
{
"status": "affected",
"version": "9.22.1.6"
},
{
"status": "affected",
"version": "9.18.4.53"
},
{
"status": "affected",
"version": "9.22.2"
},
{
"status": "affected",
"version": "9.20.3.16"
},
{
"status": "affected",
"version": "9.19.1.42"
},
{
"status": "affected",
"version": "9.18.4.57"
},
{
"status": "affected",
"version": "9.23.1.3"
},
{
"status": "affected",
"version": "9.20.3.20"
},
{
"status": "affected",
"version": "9.22.2.4"
},
{
"status": "affected",
"version": "9.23.1.7"
},
{
"status": "affected",
"version": "9.20.4"
},
{
"status": "affected",
"version": "9.22.2.9"
},
{
"status": "affected",
"version": "9.23.1.13"
},
{
"status": "affected",
"version": "9.20.4.7"
},
{
"status": "affected",
"version": "9.22.2.13"
},
{
"status": "affected",
"version": "9.18.4.66"
},
{
"status": "affected",
"version": "9.18.4.67"
},
{
"status": "affected",
"version": "9.18.4.68"
}
]
}
],
"source": "psirt@cisco.com"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*",
"matchCriteriaId": "A8F5D95D-6E80-42D2-BF57-8B3B600D6B40",
"versionEndExcluding": "9.18.4.71",
"versionStartIncluding": "9.17.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*",
"matchCriteriaId": "CE667ABD-2044-4C1E-9B75-4AD23BFF82FC",
"versionEndExcluding": "9.20.4.10",
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"versionEndExcluding": "9.23.1.19",
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}
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"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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.\r\n\r\nThis 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.\r\nNotes:\r\n\r\nExploitation of this vulnerability does not provide the attacker with root access.\r\nThe authentication, authorization, and accounting (AAA) configuration command auto-enable is not affected by this vulnerability.\u0026nbsp;\u0026nbsp;"
},
{
"lang": "es",
"value": "Una vulnerabilidad en la implementaci\u00f3n de la pila SSH propietaria con autenticaci\u00f3n basada en clave SSH en el software Cisco Secure Firewall Adaptive Security Appliance (ASA) podr\u00eda permitir a un atacante remoto no autenticado iniciar sesi\u00f3n en un dispositivo Cisco Secure Firewall ASA y ejecutar comandos como un usuario espec\u00edfico.\n\nEsta vulnerabilidad se debe a una validaci\u00f3n insuficiente de la entrada del usuario durante la fase de autenticaci\u00f3n SSH. Un atacante podr\u00eda explotar esta vulnerabilidad al enviar una entrada manipulada durante la autenticaci\u00f3n SSH a un dispositivo afectado. Un exploit exitoso podr\u00eda permitir al atacante iniciar sesi\u00f3n en el dispositivo como un usuario espec\u00edfico sin la clave SSH privada de ese usuario. Para explotar esta vulnerabilidad, el atacante debe poseer un nombre de usuario v\u00e1lido y la clave p\u00fablica asociada. La clave privada no es necesaria.\nNotas:\n\nLa explotaci\u00f3n de esta vulnerabilidad no proporciona al atacante acceso de root.\nEl comando de configuraci\u00f3n de autenticaci\u00f3n, autorizaci\u00f3n y contabilidad (AAA) auto-enable no se ve afectado por esta vulnerabilidad."
}
],
"id": "CVE-2026-20009",
"lastModified": "2026-06-17T10:16:52.453",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 1.4,
"source": "psirt@cisco.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-20009",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-03-05T15:49:23.840271Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-03-04T18:16:14.833",
"references": [
{
"source": "psirt@cisco.com",
"tags": [
"Vendor Advisory"
],
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ssh-keybypass-cr5xPUSf"
}
],
"sourceIdentifier": "psirt@cisco.com",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-138"
}
],
"source": "psirt@cisco.com",
"type": "Secondary"
}
]
}
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Sightings
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Sightings and recorded dates, grouped by day · UTC
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.