High Severity Vulnerability in Cisco Secure Firewall ASA and FTD

THREAT INTELLIGENCE

Peer Review

4.8

Proven Trust

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High

Cisco

August 11, 2026

Executive Summary

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

Key Details

Affected Platform

Cisco Secure Firewall

Attack Surface

Network accessible, unauthenticated

Recommended Action

Apply vendor patch

Affected Environment

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

Operational Impact

Successful exploitation reloads the affected firewall, causing VPN and traffic processing outage until recovery completes.

Technical Root Cause

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

Recommended Mitigation

Apply Cisco hot fixes for ASA and FTD releases immediately; verify VPN client services configuration.

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References

Cisco Product Security Incident Response Team
Bleeping Computer