CVE-2026-20039CWE-244

CVE-2026-20039

High · published March 4, 2026

CVSS v3.1
8.6
EPSS
0%
Percentile
28.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.6 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00358 · 28.9th percentile
Weakness
CWE-244 · Improper Clearing of Heap Memory Before Release ('Heap Inspection')
Published
2026-03-04T23:16Z
Affected products (10)
ProductVersionsFixed in
cisco/adaptive_security_appliance_software≥ 9.12.1, < 9.16.4.849.16.4.84
cisco/adaptive_security_appliance_software≥ 9.17.1, < 9.18.4.579.18.4.57
cisco/adaptive_security_appliance_software≥ 9.19.1, < 9.20.3.169.20.3.16
cisco/adaptive_security_appliance_software≥ 9.22.1.1, < 9.22.2.49.22.2.4
cisco/adaptive_security_appliance_software≥ 9.23.1, < 9.23.1.39.23.1.3
cisco/secure_firewall_threat_defense≥ 6.4.0, < 7.0.97.0.9
cisco/secure_firewall_threat_defense≥ 7.1.0, < 7.2.107.2.10
cisco/secure_firewall_threat_defense≥ 7.3.0, < 7.4.37.4.3
cisco/secure_firewall_threat_defense≥ 7.6.0, < 7.6.17.6.1
cisco/secure_firewall_threat_defense≥ 7.7.0, < 7.7.107.7.10
References (1)
EPSS history
Timeline
  • 04 MAR 17:17Z
    Cisco Adaptive Security Appliance and Firepower Threat Defense Software SSL VPN Authentication Denial of Service Vulnerability
    cvelistv5