High Severity Vulnerability in Cisco Secure Firewall ASA and FTD

Affected Environment
Cisco Secure Firewall ASA and FTD software running Remote Access SSL VPN or IKEv2 VPN services with client access enabled.

Threat Overview
Unauthenticated remote attacker sends crafted HTTP request to VPN service, triggering device reload and denial of service.

Exposure Timeline
Disclosed 11 August 2026, hot fixes released same window; Cisco confirmed active exploitation in the wild.

Attack Surface
Internet facing Remote Access SSL VPN and IKEv2 client services interfaces on ASA and FTD appliances.

Technical Root Cause
Insufficient error checking when processing HTTP requests sent to the SSL VPN listening service.

Exploitation Pathway
Attacker sends malformed HTTP request to exposed VPN interface, forcing an unhandled error and device reload.