A vulnerability in the OSPF protocol of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, adjacent attacker to corrupt memory on an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to memory corruption when parsing OSPF protocol packets. An attacker could exploit this vulnerability by sending crafted OSPF packets to an affected device. A successful exploit could allow the attacker to cause memory corruption causing the affected device to reboot, resulting in a DoS condition.

A vulnerability in the OSPF protocol of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, adjacent attacker to corrupt memory on an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to memory corruption when parsing OSPF protocol packets. An attacker could exploit this vulnerability by sending crafted OSPF packets to an affected device. A successful exploit could allow the attacker to cause memory corruption causing the affected device to reboot, resulting in a DoS condition.

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According to its self-reported version, Cisco ASA Software is affected by multiple vulnerabilities.

Please see the included Cisco BIDs and Cisco Security Advisory for more information.

According to its self-reported version, Cisco Secure Firewall Threat Defense (FTD) Software is affected by multiple vulnerabilities.

Please see the included Cisco BIDs and Cisco Security Advisory for more information.

ID	Name	Product	Family	Type	Severity
506210	Cisco ASA Out-of-bounds Write (CVE-2026-20023)	Tenable OT Security	Tenable.ot	Remote	medium
311450	Cisco Adaptive Security Appliance (ASA) Software OSPF DoS Vulnerabilities (cisco-sa-asaftd-ospf-ZH8PhbSW)	Nessus	CISCO	Local	medium
311444	Cisco Firepower Threat Defense (FTD) Software OSPF DoS Vulnerabilities (cisco-sa-asaftd-ospf-ZH8PhbSW)	Nessus	CISCO	Combined	medium

Detections

Analytics

CVE-2026-20023

medium

Tenable Plugins

medium

medium

medium