Cisco Adaptive Security Appliance Access Control List Bypass Vulnerability

A vulnerability in the per-user-override feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass an access control list (ACL) that is configured for an interface of an affected device. The vulnerability is due to errors that could occur when the affected software constructs and applies per-user-override rules. An attacker could exploit this vulnerability by connecting to a network through an affected device that has a vulnerable configuration. A successful exploit could allow the attacker to access resources that are behind the affected device and would typically be protected by the interface ACL.

Multiple vulnerabilities in the per-user-override feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass a configured access control list (ACL) and allow traffic that should be denied to flow through an affected device. These vulnerabilities are due to a logic error that could occur when the affected software constructs and applies per-user-override rules. An attacker could exploit these vulnerabilities by connecting to a network through an affected device that has a vulnerable configuration. A successful exploit could allow the attacker to bypass the interface ACL and access resources that would should be protected.

Cisco Adaptive Security Appliance and Firepower Threat Defense AnyConnect Access Control List Bypass Vulnerability

A vulnerability in the AnyConnect firewall for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass a configured access control list (ACL) and allow traffic that should have been denied to flow through an affected device. This vulnerability is due to a logic error in populating group ACLs when an AnyConnect client establishes a new session toward an affected device. An attacker could exploit this vulnerability by establishing an AnyConnect connection to the affected device. A successful exploit could allow the attacker to bypass configured ACL rules.

Update: On November 5, 2025, Cisco became aware of a new attack variant against devices running Cisco Secure ASA Software or Cisco Secure FTD Software releases that are affected by CVE-2025-20333 and CVE-2025-20362. This attack can cause unpatched devices to unexpectedly reload, leading to denial of service (DoS) conditions. Cisco strongly recommends that all customers upgrade to the fixed software releases that are listed in the Fixed Software ["#fs"] section of this advisory. A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to access restricted URL endpoints that are related to remote access VPN that should otherwise be inaccessible without authentication. This vulnerability is due to improper validation of user-supplied input in HTTP(S) requests. An attacker could exploit this vulnerability by sending crafted HTTP requests to a targeted web server on a device. A successful exploit could allow the attacker to access a restricted URL without authentication.

Cisco Adaptive Security Appliance and Firepower Threat Defense Software WebVPN Cross-Site Scripting Vulnerabilities

Multiple vulnerabilities in the WebVPN service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the WebVPN portal of an affected device. The vulnerabilities exist because the software insufficiently validates user-supplied input on an affected device. An attacker could exploit these vulnerabilities by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive browser-based information. An attacker would need administrator privileges on the device to exploit these vulnerabilities.

Cisco Adaptive Security Appliance Software and Cisco Firepower Threat Defense Software MOBIKE Denial of Service Vulnerability

A vulnerability in the Internet Key Exchange Version 2 Mobility and Multihoming Protocol (MOBIKE) feature for the Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a memory leak or a reload of an affected device that leads to a denial of service (DoS) condition. The vulnerability is due to the incorrect processing of certain MOBIKE packets. An attacker could exploit this vulnerability by sending crafted MOBIKE packets to an affected device to be processed. A successful exploit could cause an affected device to continuously consume memory and eventually reload, resulting in a DoS condition. The MOBIKE feature is supported only for IPv4 addresses.

DoS via TCP SYN mismanagement in Cisco ASA

A vulnerability in the handling of the embryonic connection limits in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to cause incoming TCP SYN packets to be dropped incorrectly. This vulnerability is due to improper handling of new, incoming TCP connections that are destined to management or data interfaces when the device is under a TCP SYN flood attack. An attacker could exploit this vulnerability by sending a crafted stream of traffic to an affected device. A successful exploit could allow the attacker to prevent all incoming TCP connections to the device from being established, including remote management access, Remote Access VPN (RAVPN) connections, and all network protocols that are TCP-based. This results in a denial of service (DoS) condition for affected features.

Cisco Adaptive Security Appliance (ASA) and Cisco PIX security appliance 8.0.x before 8.0(3)9 and 8.1.x before 8.1(1)1 allows remote attackers to cause a denial of service (device reload) via a crafted Transport Layer Security (TLS) packet to the device interface.

Unspecified vulnerability in Cisco Adaptive Security Appliance (ASA) and PIX 7.2 before 7.2(2)8, when using Layer 2 Tunneling Protocol (L2TP) or Remote Management Access, allows remote attackers to bypass LDAP authentication and gain privileges via unknown vectors.

Cisco Adaptive Security Appliance (ASA) and Cisco PIX security appliance 7.1.x before 7.1(2)70, 7.2.x before 7.2(4), and 8.0.x before 8.0(3)10 allows remote attackers to cause a denial of service via a crafted TCP ACK packet to the device interface.

Unspecified vulnerability in Cisco PIX 500 Series Security Appliance and 5500 Series Adaptive Security Appliance (ASA) before 7.2(3)6 and 8.0(3), when the Time-to-Live (TTL) decrement feature is enabled, allows remote attackers to cause a denial of service (device reload) via a crafted IP packet.

The DHCP relay agent in Cisco Adaptive Security Appliance (ASA) and PIX 7.2 allows remote attackers to cause a denial of service (dropped packets) via a DHCPREQUEST or DHCPINFORM message that causes multiple DHCPACK messages to be sent from DHCP servers to the agent, which consumes the memory allocated for a local buffer. NOTE: this issue only occurs when multiple DHCP servers are used.

Cisco PIX and ASA appliances with 7.1 and 7.2 software, when configured for TLS sessions to the device, allow remote attackers to cause a denial of service (device reload) via a crafted TLS packet, aka CSCsg43276 and CSCsh97120.

Cisco PIX and ASA appliances with 7.0 through 8.0 software, and Cisco Firewall Services Module (FWSM) 3.1(5) and earlier, allow remote attackers to cause a denial of service (device reload) via a crafted MGCP packet, aka CSCsi90468 (appliance) and CSCsi00694 (FWSM).

Cisco Adaptive Security Appliance (ASA) running PIX 7.0 before 7.0.7.1, 7.1 before 7.1.2.61, 7.2 before 7.2.2.34, and 8.0 before 8.0.2.11, when AAA is enabled, composes %ASA-5-111008 messages from the "test aaa" command with cleartext passwords and sends them over the network to a remote syslog server or places them in a local logging buffer, which allows context-dependent attackers to obtain sensitive information.

Race condition in Cisco Adaptive Security Appliance (ASA) and PIX 7.1 before 7.1(2)49 and 7.2 before 7.2(2)19, when using "clientless SSL VPNs," allows remote attackers to cause a denial of service (device reload) via "non-standard SSL sessions."

Cisco Adaptive Security Appliance (ASA) and Cisco PIX security appliance 8.0.x before 8.0(3)9 allows remote attackers to bypass control-plane ACLs for the device via unknown vectors.

Cisco Adaptive Security Appliance (ASA) and Cisco PIX security appliance 7.2.x before 7.2(3)2 and 8.0.x before 8.0(2)17 allows remote attackers to cause a denial of service (device reload) via a port scan against TCP port 443 on the device.

Unspecified vulnerability in Cisco Adaptive Security Appliance (ASA) and PIX 7.1 before 7.1(2)49 and 7.2 before 7.2(2)17 allows remote attackers to cause a denial of service (device reload) via unknown vectors related to VPN connection termination and password expiry.

The Instant Messenger (IM) inspection engine in Cisco Adaptive Security Appliance (ASA) and Cisco PIX security appliance 7.2.x before 7.2(4), 8.0.x before 8.0(3)10, and 8.1.x before 8.1(1)2 allows remote attackers to cause a denial of service via a crafted packet.