CVE-2024-20337: Cisco Secure Client

High severity, CVSS 8.2. EPSS: 29.9% chance of exploitation in the next 30 days.

A vulnerability in the SAML authentication process of Cisco Secure Client could allow an unauthenticated, remote attacker to conduct a carriage return line feed (CRLF) injection attack against a user. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by persuading a user to click a crafted link while establishing a VPN session. A successful exploit could allow the attacker to execute arbitrary script code in the browser or access sensitive, browser-based information, including a valid SAML token. The attacker could then use the token to establish a remote access VPN session with the privileges of the affected user. Individual hosts and services behind the VPN headend would still need additional credentials for successful access.

Affected products

• Cisco Secure Client: from 4.10.04065, before 4.10.08025 (fixed in 4.10.08025); from 5.0.00529, before 5.1.2.42 (fixed in 5.1.2.42)

Published 2024-03-06. Last modified 2026-06-17.