CVE-2023-20264: Cisco Adaptive Security Appliance Software

Medium severity, CVSS 6.1. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Cisco Adaptive Security Appliance Software: from 9.18.1, up to and including 9.18.3.46; from 9.19.1.5, up to and including 9.19.1.12
• Cisco Secure Firewall Threat Defense: version 7.2.4 only

Published 2023-11-01. Last modified 2026-08-11.