Denial of Service Vulnerability in Cisco Secure Firewall Products

CVE-2026-20349

What is CVE-2026-20349?

CVE-2026-20349 is a vulnerability found in the Remote Access SSL VPN functionality of Cisco Secure Firewall products, specifically within the Adaptive Security Appliance (ASA) Software and Threat Defense (FTD) Software. This vulnerability arises from inadequate error checking during the processing of HTTP requests, allowing an unauthenticated remote attacker to exploit the flaw. By sending specially crafted HTTP requests to the affected VPN service, a successful exploitation could result in the unexpected reloading of the device, leading to a denial of service (DoS) condition. Given that Cisco Secure Firewalls are critical in safeguarding network environments, this vulnerability could severely impact operational continuity and expose systems to additional risks by disrupting essential security functions.

Potential impact of CVE-2026-20349

1. Denial of Service (DoS): The primary impact of this vulnerability is the potential for a denial of service that could render the affected firewall inoperable. This can disrupt network traffic and essential services, making it difficult for organizations to maintain normal operations.

2. Increased Attack Surface: By enabling unauthorized access through the exploitation of this vulnerability, attackers may gain insights into the network infrastructure, potentially leading to further attacks against connected systems or exploiting additional vulnerabilities within the network.

3. Operational Disruption: Continuous unavailability caused by repeated exploitation could not only lead to immediate downtime but also result in longer-term operational disruptions, impacting business productivity and possibly harming an organization’s reputation among clients and stakeholders.

References