CVE-2026-20049
HIGHCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
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2Tags
Description
A vulnerability in the processing of Galois/Counter Mode (GCM)-encrypted Internet Key Exchange version 2 (IKEv2) IPsec traffic of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to the allocation of an insufficiently sized block of memory. An attacker could exploit this vulnerability by sending crafted GCM-encrypted IPsec traffic to an affected device. A successful exploit could allow the attacker to cause an unexpected reload of the device, resulting in a DoS condition. To exploit this vulnerability, the attacker must have valid credentials to establish a VPN connection with the affected device.
Analysis
Denial of service in Cisco ASA and FTD devices processing GCM-encrypted IKEv2 IPsec traffic results from inadequate memory allocation, allowing authenticated remote attackers to trigger device reloads by sending specially crafted encrypted packets. An attacker with valid VPN credentials can exploit this vulnerability to render affected firewalls unavailable. …
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Remediation
Within 24 hours: Inventory all Cisco ASA and FTD deployments and assess IKEv2/IPsec usage in your environment. Within 7 days: Implement network segmentation to restrict IPsec connections to trusted partners only and enable logging/alerting for IKEv2 anomalies. …
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