CVE-2026-20020
MediumCVSS 6.8Exploitation Probability (EPSS)
Low risk17th percentile - higher than 17% of all known CVEs
Summary
A vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. If OSPF authentication is enabled, the attacker must know the secret key. This is due to insufficient input validation when processing OSPF update packets. Crafted packets can cause a buffer overflow and device reload.
Risk Assessment
Risk of network service disruption due to DoS, potentially impacting availability of critical applications.
Recommendation
Update ASA/FTD software to a patched version. Enable OSPF authentication and use strong keys.
Other vulnerabilities in Cisco Secure Firewall ASA/FTD
See all- CVE-2026-20349HighActively exploited
A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall ASA and FTD Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. The issue is due to insufficient error checking when processing HTTP requests. An attacker could exploit this by sending a crafted HTTP request to the VPN service.
- CVE-2025-20362MediumActively exploited
A vulnerability in the VPN web server of Cisco Secure Firewall ASA and FTD Software allows an unauthenticated, remote attacker to access restricted URL endpoints related to remote access VPN that should be inaccessible without authentication. The issue is due to improper validation of user-supplied input in HTTP(S) requests. A successful exploit could allow access to a restricted URL without authentication.
- CVE-2025-20333CriticalActively exploited
A vulnerability in the VPN web server of Cisco Secure Firewall ASA and FTD Software allows an authenticated, remote attacker to execute arbitrary code on the device. The issue is due to improper validation of user-supplied input in HTTP(S) requests. A successful exploit could allow the attacker to execute code as root, potentially leading to full device compromise.
- CVE-2026-20021Medium
A vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, adjacent attacker to exhaust memory on an affected device, resulting in a denial of service (DoS) condition. This is due to improper input validation when parsing OSPF packets. Crafted packets can exhaust memory and cause service disruption.
- CVE-2026-20102Medium
A vulnerability in the SAML 2.0 single sign-on (SSO) feature of Cisco Secure Firewall ASA and FTD Software could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against the SAML feature and access sensitive browser-based information. This is due to insufficient input validation of HTTP parameters. Exploitation requires persuading a user to access a malicious link.
- CVE-2026-20070Medium
A vulnerability in the VPN web services component of Cisco Secure Firewall ASA and FTD Software could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a browser accessing an affected device. This is due to improper validation of user-supplied input in HTTP requests. Exploitation could allow arbitrary HTML or script execution in the context of the VPN web server.
Original NVD description (English source)
A vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. If OSPF authentication is enabled, the attacker must know the secret key to exploit this vulnerability. This vulnerability is due to insufficient input validation when processing OSPF update packets. An attacker could exploit this vulnerability by sending crafted OSPF update packets. A successful exploit could allow the attacker to create a buffer overflow, causing the affected device to reload, resulting in a DoS condition.