| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| 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. |
| A vulnerability in the AnyConnect SSL VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an implementation error within the SSL/TLS session handling process that can prevent the release of a session handler under specific conditions. An attacker could exploit this vulnerability by sending crafted SSL/TLS traffic to an affected device, increasing the probability of session handler leaks. A successful exploit could allow the attacker to eventually deplete the available session handler pool, preventing new sessions from being established and causing a DoS condition. |
| A vulnerability in the remote access VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct a brute force attack in an attempt to identify valid username and password combinations or an authenticated, remote attacker to establish a clientless SSL VPN session with an unauthorized user.
This vulnerability is due to improper separation of authentication, authorization, and accounting (AAA) between the remote access VPN feature and the HTTPS management and site-to-site VPN features. An attacker could exploit this vulnerability by specifying a default connection profile/tunnel group while conducting a brute force attack or while establishing a clientless SSL VPN session using valid credentials. A successful exploit could allow the attacker to achieve one or both of the following:
Identify valid credentials that could then be used to establish an unauthorized remote access VPN session.
Establish a clientless SSL VPN session (only when running Cisco ASA Software Release 9.16 or earlier).
Notes:
Establishing a client-based remote access VPN tunnel is not possible as these default connection profiles/tunnel groups do not and cannot have an IP address pool configured.
This vulnerability does not allow an attacker to bypass authentication. To successfully establish a remote access VPN session, valid credentials are required, including a valid second factor if multi-factor authentication (MFA) is configured.
Cisco will release software updates that address this vulnerability. There are workarounds that address this vulnerability. |
| A vulnerability 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 cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper management of authenticated sessions in the WebVPN portal. An attacker could exploit this vulnerability by authenticating with valid credentials and accessing a specific URL in the WebVPN portal. A successful exploit could allow the attacker to cause the device to reload, resulting in a temporary DoS condition. |
| Multiple vulnerabilities in Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. These vulnerabilities are due to lack of proper input validation of the HTTPS request. An attacker could exploit these vulnerabilities by sending a crafted HTTPS request to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: This vulnerability affects only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products section. |
| 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. |
| A vulnerability in the internal packet-processing functionality of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series Security Appliances could allow an unauthenticated, remote attacker to cause an affected device to stop processing traffic, resulting in a denial of service (DoS) condition. The vulnerability is due to the affected software improperly validating IP Version 4 (IPv4) and IP Version 6 (IPv6) packets after the software reassembles the packets (following IP Fragmentation). An attacker could exploit this vulnerability by sending a series of malicious, fragmented IPv4 or IPv6 packets to an affected device. A successful exploit could allow the attacker to cause Snort processes on the affected device to hang at 100% CPU utilization, which could cause the device to stop processing traffic and result in a DoS condition until the device is reloaded manually. This vulnerability affects Cisco Firepower Threat Defense (FTD) Software Releases 6.2.1 and 6.2.2, if the software is running on a Cisco Firepower 2100 Series Security Appliance. Cisco Bug IDs: CSCvf91098. |
| A vulnerability in the authentication and authorization flows for VPN connections in Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to establish a connection as a different user.
This vulnerability is due to a flaw in the authorization verifications during the VPN authentication flow. An attacker could exploit this vulnerability by sending a crafted packet during a VPN authentication. The attacker must have valid credentials to establish a VPN connection. A successful exploit could allow the attacker to establish a VPN connection with access privileges from a different user. |
| A vulnerability in the SSL/TLS client of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower 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 improper memory management when a device initiates SSL/TLS connections. An attacker could exploit this vulnerability by ensuring that the device will connect to an SSL/TLS server that is using specific encryption parameters. A successful exploit could allow the attacker to cause the affected device to unexpectedly reload, resulting in a DoS condition. |
| Multiple vulnerabilities in the Application Layer Protocol Inspection feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerabilities are due to logical errors during traffic inspection. An attacker could exploit these vulnerabilities by sending a high volume of malicious traffic across an affected device. An exploit could allow the attacker to cause a deadlock condition, resulting in a reload of an affected device. These vulnerabilities affect Cisco ASA Software and Cisco FTD Software configured for Application Layer Protocol Inspection running on the following Cisco products: 3000 Series Industrial Security Appliance (ISA), ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Adaptive Security Virtual Appliance (ASAv), Firepower 2100 Series Security Appliance, Firepower 4100 Series Security Appliance, Firepower 9300 ASA Security Module, FTD Virtual (FTDv). Cisco Bug IDs: CSCve61540, CSCvh23085, CSCvh95456. |
| A vulnerability in the Simple Network Management Protocol version 3 (SNMPv3) access control functionality of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to query SNMP data. This vulnerability is due to ineffective access control. An attacker could exploit this vulnerability by sending an SNMPv3 query to an affected device from a host that is not permitted by the SNMPv3 access control list. A successful exploit could allow the attacker to send an SNMP query to an affected device and retrieve information from the device. The attacker would need valid credentials to perform the SNMP query. |
| A vulnerability in the SSL VPN feature for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition.
This vulnerability is due to a logic error in memory management when the device is handling SSL VPN connections. An attacker could exploit this vulnerability by sending crafted SSL/TLS packets to the SSL VPN server of the affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. |
| A vulnerability in the implementation of Security Assertion Markup Language (SAML) 2.0 single sign-on (SSO) for remote access VPN in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to intercept the SAML assertion of a user who is authenticating to a remote access VPN session. This vulnerability is due to insufficient validation of the login URL. An attacker could exploit this vulnerability by persuading a user to access a site that is under the control of the attacker, allowing the attacker to modify the login URL. A successful exploit could allow the attacker to intercept a successful SAML assertion and use that assertion to establish a remote access VPN session toward the affected device with the identity and permissions of the hijacked user, resulting in access to the protected network. |
| 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. |
| A vulnerability in the Session Initiation Protocol (SIP) inspection engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload or trigger high CPU, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of SIP traffic. An attacker could exploit this vulnerability by sending SIP requests designed to specifically trigger this issue at a high rate across an affected device. Software updates that address this vulnerability are not yet available. |
| A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct directory traversal attacks and read sensitive files on a targeted system. The vulnerability is due to a lack of proper input validation of URLs in HTTP requests processed by an affected device. An attacker could exploit this vulnerability by sending a crafted HTTP request containing directory traversal character sequences to an affected device. A successful exploit could allow the attacker to view arbitrary files within the web services file system on the targeted device. The web services file system is enabled when the affected device is configured with either WebVPN or AnyConnect features. This vulnerability cannot be used to obtain access to ASA or FTD system files or underlying operating system (OS) files. |
| A vulnerability in the Simple Network Management Protocol (SNMP) feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower 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 insufficient input validation. An attacker could exploit this vulnerability by sending a crafted SNMP request to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. |
| A vulnerability in the Open Shortest Path First (OSPF) implementation of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to improper memory protection mechanisms while processing certain OSPF packets. An attacker could exploit this vulnerability by sending a series of malformed OSPF packets in a short period of time to an affected device. A successful exploit could allow the attacker to cause a reload of the affected device, resulting in a DoS condition for client traffic that is traversing the device. |
| A vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust memory resources on the affected device, leading to a denial of service (DoS) condition. The vulnerability is due to improper resource management for inbound SSL/TLS connections. An attacker could exploit this vulnerability by establishing multiple SSL/TLS connections with specific conditions to the affected device. A successful exploit could allow the attacker to exhaust the memory on the affected device, causing the device to stop accepting new SSL/TLS connections and resulting in a DoS condition for services on the device that process SSL/TLS traffic. Manual intervention is required to recover an affected device. |
| A vulnerability in the remote access VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of HTTPS requests. An attacker could exploit this vulnerability by sending crafted HTTPS requests to an affected system. A successful exploit could allow the attacker to cause resource exhaustion, resulting in a DoS condition. |
