Cisco has warned that a new vulnerability impacting Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software has been exploited in the wild. The high-severity flaw, tracked as CVE-2026-20349 (CVSS score: 8.6), is a case of insufficient error checking when processing HTTP requests that could allow an unauthenticated, remote attacker to trigger a denial-of-service (DoS) condition. "An attacker could exploit this vulnerability by sending a crafted HTTP request to the Remote Access SSL VPN service on an affected device," Cisco said in a Tuesday advisory. "A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition." The network equipment maker said the issue was found during internal security testing.