A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust device memory resulting in a denial of service (DoS) condition to new Remote Access SSL VPN connections. This does not affect the management interface, though it may become temporarily unresponsive. This vulnerability is due to trusting user input without validation. An attacker could exploit this vulnerability by sending crafted packets to the Remote Access SSL VPN server. A successful exploit could allow the attacker to cause the device web interface to stop responding, resulting in a DoS condition.

cisco cisco-sa-asa-scpcxt-filecpy-rgeP73nE: Cisco Secure Firewall Adaptive Security Appliance Software Multiple Context Mode SCP Unauthorized File Access Vulnerability

cisco cisco-sa-fmc-sql-injection-2qH6CcJd_CVE-2026-20003: Cisco Secure Firewall Management Center Software SQL Injection Vulnerabilities

cisco cisco-sa-asa-dos-FCvLD6vR: Cisco Secure Firewall Adaptive Security Appliance Software TCP Flood Denial of Service Vulnerability

cisco cisco-sa-asaftd-ospf-ZH8PhbSW_CVE-2026-20020: Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software OSPF Protocol Vulnerabilities

cisco cisco-sa-asaftd-esp-dos-uv7yD8P5: Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software IPsec Denial of Service Vulnerability

cisco cisco-sa-asaftd-ikev2-dos-eBueGdEG_CVE-2026-20013: Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software IKEv2 Denial of Service Vulnerabilities

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

  - A vulnerability in the Lua interpreter of the Remote Access SSL VPN functionality of Cisco Secure Firewall     Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could     allow an authenticated, remote attacker with valid VPN credentials to cause the device to reload     unexpectedly, resulting in a denial of service (DoS) condition. (CVE-2026-20100)

  - A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall ASA Software and Cisco     Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the     device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due     to insufficient error checking in VPN authentication message processing. (CVE-2026-20101)

  - A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall ASA Software and Cisco     Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust     device memory, resulting in a denial of service (DoS) condition to new Remote Access SSL VPN connections.
    This vulnerability is due to insufficient input validation. (CVE-2026-20103)

  - A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall ASA Software and Cisco     Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with valid VPN     credentials to exhaust device memory, resulting in a denial of service (DoS) condition. This vulnerability     is due to insufficient input validation. (CVE-2026-20105)

  - A vulnerability in the Remote Access SSL VPN, HTTP management, and MUS functionalities of Cisco Secure     Firewall ASA Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an     unauthenticated, remote attacker to exhaust device memory, resulting in a denial of service (DoS) condition     that would require a manual reboot. (CVE-2026-20106)

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

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

  - A vulnerability in the Lua interpreter of the Remote Access SSL VPN functionality of Cisco Secure Firewall     Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could     allow an authenticated, remote attacker with valid VPN credentials to cause the device to reload     unexpectedly, resulting in a denial of service (DoS) condition. (CVE-2026-20100)

  - A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall ASA Software and Cisco     Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the     device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due     to insufficient error checking in VPN authentication message processing. (CVE-2026-20101)

  - A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall ASA Software and Cisco     Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust     device memory, resulting in a denial of service (DoS) condition to new Remote Access SSL VPN connections.
    This vulnerability is due to insufficient input validation. (CVE-2026-20103)

  - A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall ASA Software and Cisco     Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with valid VPN     credentials to exhaust device memory, resulting in a denial of service (DoS) condition. This vulnerability     is due to insufficient input validation. (CVE-2026-20105)

  - A vulnerability in the Remote Access SSL VPN, HTTP management, and MUS functionalities of Cisco Secure     Firewall ASA Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an     unauthenticated, remote attacker to exhaust device memory, resulting in a denial of service (DoS) condition     that would require a manual reboot. (CVE-2026-20106)

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

ID	Name	Product	Family	Severity
311458	Cisco Firepower Threat Defense (FTD) Software VPN DoS Vulnerabilities (cisco-sa-asaftd-vpn-m9sx6MbC)	Nessus	CISCO	high
311445	Cisco Adaptive Security Appliance (ASA) Software VPN DoS Vulnerabilities (cisco-sa-asaftd-vpn-m9sx6MbC)	Nessus	CISCO	high

Detections

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CVE-2026-20103

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