Double free in Cisco Firewall Threat Defense (FTD) and Cisco Adaptive Security Appliance (ASA) - CVE-2025-20134
Published: August 19, 2025
Vulnerability identifier: #VU114228
CSH Severity: Medium
CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2025-20134
CWE-ID: CWE-415
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a boundary error when parsing SSL/TLS certificates. A remote attacker can send specially crafted DNS packets that match a static Network Address Translation (NAT) rule with DNS inspection enabled through an affected device, trigger a double free error and perform a denial of service (DoS) attack.
Affected software
Cisco Firewall Threat Defense (FTD)
Cisco Adaptive Security Appliance (ASA)
Cisco Adaptive Security Appliance (ASA)
How to mitigate CVE-2025-20134
Install update from vendor's website.
Cisco Firewall Threat Defense (FTD) - update to 7.0
Cisco Adaptive Security Appliance (ASA) - update to 9.16
Cisco Adaptive Security Appliance (ASA) - update to 9.16