CVE-2026-20039
published 2026-03-04CVE-2026-20039: A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD)…
PriorityP352high8.6CVSS 3.1
AVNACLPRNUINSCCNINAH
EPSS
0.36%
28.1th percentile
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.
Affected
221 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| cisco | adaptive_security_appliance_software | >= 9.12.1 < 9.16.4.84 | 9.16.4.84 |
| cisco | adaptive_security_appliance_software | >= 9.17.1 < 9.18.4.57 | 9.18.4.57 |
| cisco | adaptive_security_appliance_software | >= 9.19.1 < 9.20.3.16 | 9.20.3.16 |
| cisco | adaptive_security_appliance_software | >= 9.22.1.1 < 9.22.2.4 | 9.22.2.4 |
| cisco | adaptive_security_appliance_software | >= 9.23.1 < 9.23.1.3 | 9.23.1.3 |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
| cisco | cisco_secure_firewall_adaptive_security_appliance_software | — | — |
CVSS provenance
nvdv3.18.6HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
vendor_cisco8.6HIGH
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GHSA
GHSA-ch3j-whf9-3xp2: A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FT
ghsa_unreviewed·2026-03-04
CVE-2026-20039 [HIGH] CWE-244 GHSA-ch3j-whf9-3xp2: A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FT
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.
Cisco
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software VPN Web Server Denial of Service Vulnerability
vendor_cisco·2026-03-04·CVSS 8.6
CVE-2026-20039 [HIGH] CWE-244 Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software VPN Web Server Denial of Service Vulnerability
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software VPN Web Server Denial of Service Vulnerability
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.
Cisco has released software updates that address this vulnerability. T
Cisco
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software VPN Web Server Denial of Service Vulnerability
vendor_cisco·CVSS 3.1
CVE-2026-20039 Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software VPN Web Server Denial of Service Vulnerability
CVE-2026-20039: Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software VPN Web Server Denial of Service Vulnerability
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. Cisco has released software updates that address this vul
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-03-04
Published