CVE-2026-20039
Cisco Adaptive Security Appliance and Firepower Threat Defense Software SSL VPN Authentication Denial of Service Vulnerability
In short
A flaw in Cisco's firewall VPN web server allows attackers to crash the device by sending specially crafted HTTP requests, causing it to restart and become unavailable. Anyone on the internet can trigger this without needing a password.
Technical detail
Improper memory management in the VPN web server of Cisco ASA and FTD allows remote unauthenticated attackers to cause device reload via crafted HTTP requests. Attack vector is network-based with no authentication required; successful exploitation results in denial of service.
Summary generated and translated by AI from the official description.
A vulnerability in the VPN web server 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 a denial of service (DoS) condition on an affected device.
This vulnerability is due to ineffective memory management of the VPN web server. An attacker could exploit this vulnerability by sending a large number of crafted HTTP requests to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Affected products
Cisco · Cisco Secure Firewall Adaptive Security Appliance (ASA) SoftwareCisco · Cisco Secure Firewall Threat Defense (FTD) SoftwareWant to know if your infrastructure is exposed to this?
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