CERT-In warns of denial-of-service risk in Cisco ASA and FTD VPN software

What happened

CERT-In published vulnerability note CIVN-2026-0534 on November 2, 2026, describing a denial-of-service weakness in Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD). The note references CVE-2026-76418 and rates the issue high severity.

Affected systems and impact

CERT-In identifies a range of ASA and FTD software releases as affected. The weakness is described as a logic error relating to secondary authentication on an SSL remote access VPN tunnel group. A remote attacker sending a specially crafted request may cause service disruption.

Recommended action

Organizations operating Cisco ASA or FTD should check whether their versions and VPN configurations match the advisory, consult Cisco's original security advisory, and apply the vendor's recommended fixes or mitigations. Prioritize externally accessible VPN gateways.

Source and verification

This is a CyberGeek News summary of CERT-In vulnerability note CIVN-2026-0534 dated November 2, 2026. It does not independently establish whether exploitation has occurred at any specific organization.