Cisco Systems has disclosed a denial-of-service vulnerability in its Cisco Secure Firewall ASA and Cisco Secure Firewall FTD products. The flaw, identified as CVE-2026-76418, affects the SSL VPN functionality and has already been exploited in the wild.
According to the security advisory published on 28 October 2026, the vulnerability impacts configurations where secondary authentication is enabled for tunnel groups within the SSL remote access VPN login service. An unauthenticated attacker can send a crafted request during the SSL VPN connection process, forcing the device to reboot and causing a service denial condition.
The CVSS v3.1 base score for the issue is 8.6, placing it in the High severity category. Cisco confirmed exploitation activity targeting the products in October 2026.
Patches addressing the vulnerability are now available for both Cisco Secure Firewall ASA and Cisco Secure Firewall FTD. The vendor urges all customers to apply the updates without delay to mitigate the risk of further attacks.


