CVE-2026-76418
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Tunnel Denial of Service Vulnerability
What happened?
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.
Affected software and versions
| Software | Version information | Fixed version |
|---|---|---|
| Cisco Secure Firewall Adaptive Security Appliance (ASA) SoftwareCisco | affected: 9.16.1; affected: 9.16.1.28; affected: 9.16.2; affected: 9.16.2.3; affected: 9.16.2.7; affected: 9.16.2.11; affected: 9.16.2.13; affected: 9.16.2.14; affected: 9.16.3.3; affected: 9.16.3; affected: 9.16.3.14; affected: 9.18.1; affected: 9.16.3.15; affected: 9.18.1.3; affected: 9.18.2; affected: 9.16.3.19; affected: 9.16.3.23; affected: 9.18.2.5; affected: 9.16.4; affected: 9.18.2.7; affected: 9.19.1; affected: 9.16.4.9; affected: 9.18.2.8; affected: 9.16.4.14; affected: 9.18.3; affected: 9.19.1.5; affected: 9.16.4.18; affected: 9.19.1.9; affected: 9.18.3.39; affected: 9.16.4.19; affected: 9.19.1.12; affected: 9.18.3.46; affected: 9.16.4.27; affected: 9.19.1.18; affected: 9.18.3.53; affected: 9.18.3.55; affected: 9.16.4.38; affected: 9.16.4.39; affected: 9.18.3.56; affected: 9.20.1; affected: 9.16.4.42; affected: 9.19.1.22; affected: 9.18.4; affected: 9.20.1.5; affected: 9.18.4.5; affected: 9.19.1.24; affected: 9.16.4.48; affected: 9.18.4.8; affected: 9.20.2; affected: 9.19.1.27; affected: 9.16.4.55; affected: 9.18.4.22; affected: 9.20.2.10; affected: 9.16.4.57; affected: 9.19.1.28; affected: 9.18.4.24; affected: 9.20.2.21; affected: 9.16.4.61; affected: 9.19.1.31; affected: 9.18.4.29; affected: 9.20.2.22; affected: 9.16.4.62; affected: 9.18.4.34; affected: 9.20.3; affected: 9.16.4.67; affected: 9.16.4.70; affected: 9.18.4.40; affected: 9.23.1; affected: 9.22.1.1; affected: 9.16.4.71; affected: 9.20.3.4; affected: 9.18.4.47; affected: 9.20.3.7; affected: 9.19.1.37; affected: 9.16.4.76; affected: 9.20.3.9; affected: 9.19.1.38; affected: 9.18.4.50; affected: 9.22.1.3; affected: 9.20.3.10; affected: 9.22.1.2; affected: 9.18.4.52; affected: 9.20.3.13; affected: 9.22.1.6; affected: 9.18.4.53; affected: 9.16.4.82; affected: 9.22.2; affected: 9.20.3.16; affected: 9.19.1.42; affected: 9.18.4.57; affected: 9.16.4.84; affected: 9.23.1.3; affected: 9.20.3.20; affected: 9.22.2.4; affected: 9.23.1.7; affected: 9.20.4; affected: 9.22.2.9; affected: 9.23.1.13; affected: 9 | See vendor advisory |
| Cisco Secure Firewall Threat Defense (FTD) SoftwareCisco | affected: 7.0.0; affected: 7.0.0.1; affected: 7.0.1; affected: 7.0.1.1; affected: 7.0.2; affected: 7.2.0; affected: 7.0.2.1; affected: 7.0.3; affected: 7.2.0.1; affected: 7.0.4; affected: 7.2.1; affected: 7.0.5; affected: 7.3.0; affected: 7.2.2; affected: 7.2.3; affected: 7.3.1; affected: 7.2.4; affected: 7.0.6; affected: 7.2.5; affected: 7.2.4.1; affected: 7.3.1.1; affected: 7.4.0; affected: 7.0.6.1; affected: 7.2.5.1; affected: 7.4.1; affected: 7.2.6; affected: 7.0.6.2; affected: 7.4.1.1; affected: 7.2.7; affected: 7.2.5.2; affected: 7.3.1.2; affected: 7.2.8; affected: 7.6.0; affected: 7.4.2; affected: 7.2.8.1; affected: 7.0.6.3; affected: 7.4.2.1; affected: 7.2.9; affected: 7.0.7; affected: 7.7.0; affected: 7.4.2.2; affected: 7.2.10; affected: 7.6.1; affected: 7.4.2.3; affected: 7.0.8; affected: 7.6.2; affected: 7.7.10; affected: 7.7.11; affected: 7.0.8.1; affected: 7.6.2.1; affected: 7.7.10.1; affected: 7.4.2.4; affected: 7.2.10.2; affected: 7.4.3; affected: 7.6.4; affected: 10.0.0; affected: 7.4.4; affected: 7.0.9; affected: 7.2.11; affected: 7.4.7; affected: 7.4.8; affected: 7.2.12; affected: 7.6.6; affected: 7.7.13; affected: 10.0.2; affected: 7.0.10; affected: 10.1.0 | See vendor advisory |
Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.
Is it being exploited?
CISA lists this CVE in its Known Exploited Vulnerabilities catalogue. Added 2026-10-29.
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
How to respond
- Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
- Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
- Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.