Actively exploited in the wild
Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Vulnerability
Cisco - Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) · Listed in the CISA KEV since 2026-08-11. This indicates confirmed attacks in production environments.
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CVE-2026-20349
HighCVSS 8.6KEVExploitation Probability (EPSS)
High risk82th percentile - higher than 82% of all known CVEs
Summary
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.
Risk Assessment
An attacker can cause unavailability of the firewall device, potentially disrupting network traffic and access to resources. The vulnerability can be exploited remotely without authentication, posing a serious risk.
Recommendation
Apply patches provided by Cisco for ASA and FTD. Also restrict access to the Remote Access SSL VPN service to trusted sources only.
Other vulnerabilities in Cisco Secure Firewall ASA/FTD
See all- 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-2026-20121Medium
A vulnerability in the access control list (ACL) Object Group Search (OGS) implementation of Cisco Secure Firewall ASA Software and Cisco Secure Firewall Threat Defense (FTD) Software. It is due to a logic error in populating group access control policies (ACPs) with OGS configured. An unauthenticated, remote attacker could send traffic that should be blocked and bypass configured access controls.
- CVE-2026-20120Medium
A vulnerability in the access control list (ACL) Object Group Search (OGS) implementation of Cisco Secure Firewall ASA Software and Cisco Secure Firewall Threat Defense (FTD) Software. It is due to a logic error in populating group access control policies (ACPs) with OGS configured. An unauthenticated, remote attacker could send traffic that should be blocked and bypass configured access controls.
- 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-2026-20020Medium
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.
- 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.
- CVE-2025-20224Medium
A vulnerability in the IKEv2 module of Cisco Secure Firewall ASA and FTD software could allow an unauthenticated, remote attacker to trigger a memory leak, resulting in a denial of service (DoS) condition. The issue is due to improper parsing of IKEv2 packets.
Original NVD description (English source)
A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to insufficient error checking when processing HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the Remote Access SSL VPN service on an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS