cisco-sa-asaftd-desync-n5AVzEQwMediumCVSS 4.3

Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software VPN Web Services Client-Side Request Smuggling Vulnerability

Published
March 4, 2026
Last Modified
March 4, 2026

🔗 CVE IDs covered (1)

CVE-2026-20069 →

📋 Description

A vulnerability in the VPN web services component of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct browser-based attacks against users of an affected device.

This vulnerability is due to improper validation of HTTP requests. An attacker could exploit this vulnerability by persuading a user to visit a website that is designed to pass malicious HTTP requests to a device that is running Cisco Secure Firewall ASA Software or Cisco Secure FTD Software and has web services endpoints supporting VPN features enabled. A successful exploit could allow the attacker to reflect malicious input from the affected device to the browser that is in use and conduct browser-based attacks, including cross-site scripting (XSS) attacks. The attacker is not able to directly impact the affected device.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is part of the March 2026 release of the Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2026 Semiannual Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75736"].

CVE-2026-20069 — Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software VPN Web Services Client-Side Request Smuggling Vulnerability (CVSS 3.1 4.3, CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N)

🎯 Affected products240

  • Cisco 3000 Series Industrial Security Appliances (ISA)
  • Cisco ASA 5500-X Series Firewalls
  • Cisco Adaptive Security Virtual Appliance (ASAv)
  • Cisco Firepower 1000 Series
  • Cisco Firepower 2100 Series
  • Cisco Firepower 4100 Series
  • Cisco Firepower 9000 Series
  • Cisco Secure Firewall 1200 Series
  • Cisco Secure Firewall 3100 Series
  • Cisco Secure Firewall 4200 Series
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
  • Cisco Secure Firewall Threat Defense (FTD) Software
  • Cisco Secure Firewall Threat Defense Virtual
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1.2
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1.3
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.1
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.4
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.5
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.9
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.3
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.3.12
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.3.2
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.3.7
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.3.9
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.10
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.13
  • Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.18
  • +210 more not shown

✅ Remediation

Cisco has released software updates that address this vulnerability. https://software.cisco.com Workarounds: There are no workarounds that address this vulnerability.

🔗 References (7)