CVE-2026-76418: Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability

Vulnerability summary

CVE-2026-76418 is a high (CVSS 8.6) vulnerability in Cisco Secure Firewall ASA Software and Cisco Secure FTD Software. It is known to be exploited: CISA lists it, first on 29-10-2026. EPSS estimates a 0.57% chance of exploitation in the next 30 days, higher than 47.3% of scored vulnerabilities.

Timeline

1. 28-10-2026
   PublishedVulnerability first disclosed.
2. 29-10-2026
   Added to CISA KEVExploitedCisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability
3. 30-10-2026
   Last modifiedVulnerability information updated.
4. 01-11-2026
   CISA remediation dueUpcomingApply mitigations per vendor instructions.

Description

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.

• CWE-690Unchecked Return Value to NULL Pointer DereferenceThe product does not check for an error after calling a function that can return with a NULL pointer if the function fails, which leads to a resultant NULL pointer dereference.