Cisco firewalls face active exploitation of high-severity vulnerability

A high-severity vulnerability, identified as CVE-2026-20349, is currently being exploited in the wild to target Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) software. The flaw carries a CVSS score of 8.6.

Unauthenticated remote attackers can exploit the vulnerability by sending a specially crafted HTTP request to an affected Remote Access SSL VPN service. This triggers an unexpected reload of the appliance, resulting in a denial-of-service (DoS) condition. The attack is noted for its low complexity, as it requires no stolen credentials or user interaction to disrupt network availability.