Cisco released fixes on Wednesday for a remotely exploitable zero-day in its Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) software, tracked as CVE-2026-76418 with a CVSS score of 8.6. The flaw resides in the Remote Access SSL VPN service and allows unauthenticated attackers to send a malicious request that forces the device to restart, disrupting availability. Exploitation requires an unpatched release, a reachable SSL VPN login service, and a tunnel group using secondary authentication. Cisco notes that its cloud-delivered firewall, Secure Access, and Secure Firewall Management Center are not vulnerable. No workarounds exist, though customers may reduce exposure by disabling the tunnel-group list or removing secondary authentication, which Cisco cautions weakens VPN security. This is the second ASA/FTD zero-day used for DoS attacks after CVE-2026-20349 in August. 1