Cisco patches critical ASA/FTD zero day as attacks spike

CISCO has released patches for a zero-day vulnerability (CVE-2026-20349) affecting its Secure Firewall ASA and FTD software. This vulnerability allows unauthenticated remote attackers to cause denial-of-service (DoS) conditions by sending specially crafted HTTP requests. Cisco noted active exploitation of this flaw was detected in August 2026. CISA has added this vulnerability to its Known Exploited Vulnerabilities catalog, urging timely patching. This is the twelfth Cisco-related CVE added this year, highlighting ongoing security issues in its products.