CVE-2026-76418CiscoFirewall and VPNOctober 28, 2026

Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Tunnel Denial of Service Vulnerability

High 8.6Actively exploited

Description

A vulnerability in the Remote Access SSL VPN service of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to logic errors when secondary authentication is configured on a tunnel group. An attacker could exploit this vulnerability by sending a crafted request when connecting to the SSL remote access VPN. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-tunnel-dos-s6mgkb75 Security Impact Rating: High CVE: CVE-2026-76418

What to do

Install the fixed versions listed in the official advisory. If you cannot update right away, apply the workarounds or mitigations it describes and limit access to the affected service.

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Details

Vendor
Cisco
Product
Cisco Secure Firewall ASA e FTD
CVE
CVE-2026-76418
Affected versions
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.16: 38 versions, from 9.16.1 to 9.16.4.103
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.18: 34 versions, from 9.18.1 to 9.18.4.135
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.19: 13 versions, from 9.19.1 to 9.19.1.42
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.20: 26 versions, from 9.20.1 to 9.20.4.235
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.23: 10 versions, from 9.23.1 to 9.23.1.195
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.22: 14 versions, from 9.22.1.1 to 9.22.3.26
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.24: 7 versions, from 9.24.1 to 9.24.10
Cisco Secure Firewall Threat Defense (FTD) Software 7.0: 18 versions, from 7.0.0 to 7.0.10
Cisco Secure Firewall Threat Defense (FTD) Software 7.2: 19 versions, from 7.2.0 to 7.2.12
Cisco Secure Firewall Threat Defense (FTD) Software 7.3: 4 versions, from 7.3.0 to 7.3.1.2
Cisco Secure Firewall Threat Defense (FTD) Software 7.4: 12 versions, from 7.4.0 to 7.4.8
Cisco Secure Firewall Threat Defense (FTD) Software 7.6: 6 versions, from 7.6.0 to 7.6.6
Cisco Secure Firewall Threat Defense (FTD) Software 7.7: 5 versions, from 7.7.0 to 7.7.13
Cisco Secure Firewall Threat Defense (FTD) Software 10.0: 10.0.0; 10.0.2
Cisco Secure Firewall Threat Defense (FTD) Software 10.1: 10.1.0 (from the advisory and NVD; check the exact builds in the official advisory)
CVSS score
8.6
Actively exploited
Yes, listed in the CISA Known Exploited Vulnerabilities catalog
Source
Cisco PSIRT – original advisory
Published
October 28, 2026

The description and the recommended action are quoted from the public advisory (the action is our generic advice); severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.

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