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.
The CVSS score of this vulnerability is 7.7, categorizing it as high severity. This score indicates a significant risk to organizations, as the availability of critical network devices may be compromised. With the potential for devices to unexpectedly reload, organizations must recognize the urgency to address this vulnerability.
Cisco has classified this vulnerability as analyzed, and it is essential for organizations utilizing affected Cisco products to prioritize remediation efforts. The exploitation status indicates that no public exploit has been confirmed, but the risk remains due to the potential for crafted traffic to trigger the vulnerability.
Organizations should prioritize patching immediately. Implementing the latest updates from Cisco will help mitigate the risk of exploitation. Additionally, continuous monitoring of network traffic for unusual patterns may assist in identifying potential abuse of this vulnerability.
Vulnerability Details
Cisco's vulnerability is classified under CWE-131, which pertains to incorrect calculation of buffer size leading to insufficient memory allocation. The affected products include both the Adaptive Security Appliance Software and the Firepower Threat Defense Software, specifically versions that fall within certain ranges outlined in the configurations.
The vulnerability was published on March 4, 2026, and affects multiple versions of the Cisco Adaptive Security Appliance and Cisco Firepower Threat Defense. Organizations should refer to their Cisco support channels for detailed guidance on the specific versions affected and available patches.
Technical Analysis
The root cause of this vulnerability is the insufficient memory allocation within the software's processing of GCM-encrypted IKEv2 IPsec traffic. Attackers may leverage this flaw by sending specially crafted packets to the device, necessitating low privileges (an authenticated user) to initiate the attack.
The attack vector is network-based, allowing the attacker to target devices remotely. The attack complexity is low, as no significant barriers exist for an authenticated attacker to exploit this vulnerability, and user interaction is not required. The impact on availability is high, as successful exploitation may lead to device reboots.
Risk & Impact Analysis
Risk to organizations includes the potential for denial of service, which could disrupt critical network operations. The blast radius of this vulnerability may vary, but it poses risks to any connected services relying on the Cisco devices in question. Given the nature of network devices, the urgency assessment is high due to the operational impact of outages.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of Cisco Secure Firewall Adaptive Security Appliance Software include: 9.18.1 to less than 9.18.4.66, 9.19.1 to less than 9.20.3.20, 9.22.1.1 to less than 9.22.2.4, and 9.23.1 to less than 9.23.1.3. For Cisco Firepower Threat Defense Software, vulnerable versions are from 7.2.0 to less than 7.2.11, 7.3.0 to less than 7.4.3, 7.6.0 to less than 7.6.4, and 7.7.0 to less than 7.7.10.
Mitigation & Remediation
Organizations should address this vulnerability by applying the necessary patches provided by Cisco. It is critical to upgrade to the latest version of the Adaptive Security Appliance and Firepower Threat Defense Software to mitigate risks associated with this vulnerability. In cases where immediate patching is not feasible, organizations should consider implementing network controls to limit access to affected devices, ensuring that only authorized users can establish VPN connections.
For further guidance on penetration testing and identifying vulnerabilities, organizations may explore penetration testing services that can help assess their security posture.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor logs for unusual traffic patterns, specifically related to IPsec connections. Behavioral anomalies such as unexpected device reboots or unusual authentication attempts should be investigated promptly. Additionally, network signatures may be employed to identify crafted GCM-encrypted packets that could be indicative of an attempted exploit.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2026-20049 lies in its demonstration of how critical network devices can be vulnerable to specific traffic patterns that may lead to service disruption. This vulnerability highlights the need for organizations to continuously assess their security measures surrounding firewall and VPN infrastructure. The pattern of exploitation represents a potential trend where attackers leverage known traffic processing vulnerabilities.
Organizations should take this incident as a strategic defensive takeaway to enhance their monitoring capabilities and ensure that security patches are applied promptly. For further reading on continuous security practices, organizations can reference penetration testing methodology and how to build a robust security program.
Engaging with security testing professionals can provide insights into emerging threats and how to best protect against them. For organizations seeking to improve their security posture, understanding the implications of vulnerabilities like CVE-2026-20049 is crucial.
For additional resources on vulnerability management, organizations can explore vulnerability management program design to strengthen their defenses.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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