Cisco Secure Firewall Adaptive Security Appliance Software IKEv2 memory leak

Summaryinfo

A vulnerability was found in Cisco Secure Firewall Adaptive Security Appliance Software and Secure Firewall Threat Defense Software and classified as problematic. The affected element is an unknown function of the component IKEv2. Executing a manipulation can lead to memory leak. This vulnerability is tracked as CVE-2026-20015. The attack can be launched remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Cisco Secure Firewall Adaptive Security Appliance Software and Secure Firewall Threat Defense Software (the affected version is unknown) and classified as problematic. This vulnerability affects an unknown code of the component IKEv2. The manipulation with an unknown input leads to a memory leak vulnerability. The CWE definition for the vulnerability is CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. As an impact it is known to affect availability. CVE summarizes:

A vulnerability in the IKEv2 feature of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device that may impact the availability of services to devices elsewhere in the network. This vulnerability is due to a memory leak when parsing IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device. A successful exploit could allow the attacker to exhaust resources, causing a DoS condition that will eventually require the device to be manually reloaded.

The advisory is shared for download at sec.cloudapps.cisco.com. This vulnerability was named CVE-2026-20015 since 10/08/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 03/04/2026). The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Firewall Software

Vendor

• Cisco

Name

• Secure Firewall Adaptive Security Appliance Software
• Secure Firewall Threat Defense Software

License

• commercial

Website

• Vendor: https://www.cisco.com/

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