Adaptive Security Appliance Software vulnerabilities
48 known vulnerabilities in Adaptive Security Appliance Software from Cisco. 44 are rated high or critical, and 15 have been exploited in real attacks. Each entry lists the affected versions and the release that fixes it, where the vendor has published one.
Latest first
- 8.6 High severity
Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Exploited
A vulnerability in the Remote Access SSL VPN service of 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 unexp
- 8.6 High severity
Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Exploited
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 unex
- 8.6 High severity
IOS: Missing Release of Memory after Effective Lifetime
A vulnerability in the Internet Key Exchange version 2 (IKEv2) feature of Cisco IOS Software, Cisco IOS XE Software, Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauth
- 7.7 High severity
Cisco Secure Firewall Adaptive Security…: Missing Release of Memory after Effective Lifetime
A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with a valid VPN connection to exhaus
- 8.6 High severity
Cisco Secure Firewall Adaptive Security…: Allocation of Resources Without Limits or Throttling
A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust device memory resulting
- 8.6 High severity
Cisco Secure Firewall Adaptive Security…: Use of Insufficiently Random Values
A vulnerability in the SAML 2.0 single sign-on (SSO) feature of Cisco Secure Firewall ASA Software and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a DoS condition. This vulnerabil
- 7.7 High severity
Cisco Secure Firewall Adaptive Security…: Buffer Copy without Checking Size of Input
A vulnerability in the LUA interperter of the Remote Access SSL VPN feature of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with a valid VPN con
- 8.6 High severity
Cisco Secure Firewall Adaptive Security…: Missing Release of Resource after Effective Lifetime
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 vulnerabili
- 7.7 High severity
Cisco Secure Firewall Adaptive Security…: Incorrect Calculation of Buffer Size
A vulnerability in the processing of Galois/Counter Mode (GCM)-encrypted Internet Key Exchange version 2 (IKEv2) IPsec traffic of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could all
- 8.6 High severity
Cisco Secure Firewall Adaptive Security…: Improper Clearing of Heap Memory Before Release
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 cause a denial of service (DoS) condition on an
- 7.7 High severity
Cisco Secure Firewall Adaptive Security…: Missing Release of Memory after Effective Lifetime
A vulnerability in the IKEv2 feature of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an authenticated, remote attacker with valid VPN user credentials to cause a DoS condition on an affected device that may also impact the avail
- 9.0 Critical severity
IOS: Heap-based Buffer Overflow
A vulnerability in the web services of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, Cisco Secure Firewall Threat Defense (FTD) Software, Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an unauthenticated, r
- 8.6 High severity
Cisco Secure Firewall Adaptive Security (ASA) Appliance and Secure Firewall Threat Defense (FTD) Missing Authorization Exploited
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 u
- 9.9 Critical severity
Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Exploited
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 authenticated, remote attacker to execute arbitrary code on an affected device. Thi
- 7.7 High severity
Cisco Adaptive Security Appliance (ASA) Software: Improper Resource Shutdown or Release
A vulnerability in the TLS 1.3 implementation for a specific cipher for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software for Cisco Firepower 3100 and 4200 Series devices could allow an aut
- 8.6 High severity
Cisco Adaptive Security Appliance (ASA) Software: Out-of-bounds Write
A vulnerability in the Internet Key Exchange version 2 (IKEv2) protocol processing of Cisco Adaptive Security Appliance (ASA) Software, Cisco Firepower Threat Defense (FTD) Software, Cisco IOS Software, and Cisco IOS XE Software could allow an unauthenticated,
- 8.6 High severity
A vulnerability in the Remote Access VPN feature of Cisco Adaptive Security Appliance (ASA)…
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 the device to reload unexpectedly, resulting in a de
- 8.6 High severity
Cisco Adaptive Security Appliance (ASA) Software: Improper Validation of Specified Type of Input
A vulnerability in the TLS cryptography functionality of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in
- 5.8 Medium severity
Cisco ASA and FTD Denial-of-Service Exploited
A vulnerability in the Remote Access VPN (RAVPN) service 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) of the RAVPN servi
- 8.6 High severity
Cisco Adaptive Security Appliance (ASA) Software: NULL Pointer Dereference
A vulnerability in the Internet Key Exchange version 2 (IKEv2) protocol for VPN termination of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial
- 7.7 High severity
Cisco Adaptive Security Appliance (ASA) Software: Improper Validation of Specified Type of Input
A vulnerability in the Dynamic Access Policies (DAP) feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to cause an affected device to reload unexpectedly.
- 8.6 High severity
Cisco Adaptive Security Appliance (ASA) Software: Access of Memory Location After End of Buffer
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 den
- 9.9 Critical severity
Cisco Adaptive Security Appliance (ASA) Software: Improper Neutralization of Expression/Command Delimiters
A vulnerability in the SSH subsystem of Cisco Adaptive Security Appliance (ASA) Software could allow an authenticated, remote attacker to execute operating system commands as root. This vulnerability is due to insufficient validation of user input. An attacker
- 7.7 High severity
Cisco Adaptive Security Appliance (ASA) Software: Improper Handling of Extra Values
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 an unexpected reload of the de
- 8.6 High severity
Cisco Secure Firewall Adaptive Security…: Memory Allocation with Excessive Size Value
Update for September 16, 2026: The original 1.0 version of this advisory was specific to the Cisco Adaptive Security Virtual Appliance (ASAv) and Cisco Secure Firewall Threat Defense Virtual (FTDv) models. However, it was later found that this vulnerability af
- 6.0 Medium severity
Cisco ASA and FTD Privilege Escalation Exploited
A vulnerability in a legacy capability that allowed for the preloading of VPN clients and plug-ins and that has been available in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, l
- 8.6 High severity
Cisco ASA and FTD Denial of Service Exploited
A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting i
- 8.6 High severity
Cisco Adaptive Security Appliance (ASA) Software: Missing Release of Resource after Effective Lifetime
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 d
- 8.6 High severity
Cisco Adaptive Security Appliance (ASA) Software: Improper Resource Shutdown or Release
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
- 8.6 High severity
Cisco Adaptive Security Appliance (ASA) Software: Uncaught Exception
A vulnerability in ICMPv6 processing 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. This vulnerability is due t
- 9.1 Critical severity
Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Exploited
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 val
- 7.5 High severity
Cisco Adaptive Security Appliance (ASA) Software: Incorrect Conversion between Numeric Types
A vulnerability in the hardware-based SSL/TLS cryptography functionality of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series Appliances could allow an unauthenticated, remote att
- 7.5 High severity
Cisco Adaptive Security Appliance (ASA) Software: Improper Restriction of Operations within the Bounds of a Memory Buffer
A vulnerability in dynamic access policies (DAP) functionality of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a
- 7.5 High severity
Cisco Adaptive Security Appliance (ASA) Software: Observable Discrepancy
A vulnerability in the handling of RSA keys on devices running Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to retrieve an RSA private key. This vulnerability
- 7.5 High severity
Cisco Adaptive Security Appliance (ASA) Software: Uncontrolled Resource Consumption
A vulnerability in the DNS inspection handler of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service condition (DoS) on an affected device. Th
- 8.8 High severity
Cisco Adaptive Security Appliance (ASA) Software: Improper Privilege Management
A vulnerability in the web services interface for remote access VPN features of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, but unprivileged, remote attacker to elevate privil
- 7.5 High severity
A vulnerability in the web services interface for remote access VPN features of Cisco Adaptive…
A vulnerability in the web services interface for remote access VPN features 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
- 7.4 High severity
Cisco Adaptive Security Appliance (ASA) Software: Missing Cryptographic Step
A vulnerability in an IPsec VPN library of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to read or modify data within an IPsec IKEv2 VPN tunnel. This vulnerab
- 7.1 High severity
Cisco Adaptive Security Appliance (ASA) Software: Out-of-bounds Write
A vulnerability in the handler for HTTP authentication for resources accessed through the Clientless SSL VPN portal of Cisco Adaptive Security Appliance (ASA) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition o
- 8.6 High severity
A vulnerability in the remote access SSL VPN features of Cisco Adaptive Security Appliance…
A vulnerability in the remote access SSL VPN features 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 affec