CVE-2026-76418
Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability
Cisco Secure Firewall ASA Software and Cisco Secure FTD Software
A vulnerability in the Remote Access SSL VPN service of Cisco Secure Firewall Adaptive Security Appliance (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 logic errors when secondary authentication is configured on a tunnel group. An attacker could exploit this vulnerability by sending a crafted request when connecting to the SSL remote access VPN. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 29 October 2026. US federal agencies were required to remediate it by 1 November 2026.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 0.8%, which is higher than 57.4% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Frequently asked questions
Is CVE-2026-76418 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2026-76418.
What does CVE-2026-76418 affect?
CVE-2026-76418 affects Cisco Secure Firewall ASA Software and Cisco Secure FTD Software. A vulnerability in the Remote Access SSL VPN service of Cisco Secure Firewall Adaptive Security Appliance (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 logic errors when secondary authentication is configured on a tunnel group. An attacker could exploit this vulnerability by sending a crafted request when connecting to the SSL remote access VPN. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.
How severe is CVE-2026-76418?
CVE-2026-76418 is rated HIGH with a CVSS base score of 8.6. EPSS puts the probability of exploitation in the next 30 days at 0.8%, higher than 57.4% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 1 November 2026.
How should organisations respond to CVE-2026-76418?
Apply the vendor patch for Cisco Secure Firewall ASA Software and Cisco Secure FTD Software as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.