Secure Client (AnyConnect)
CVE-2024-20337: A vulnerability in the SAML authentication process of Cisco Secure Client could allow an unauthenticated, r…
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.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Cisco Secure Client 4.9 | See the advisory |
| Cisco Secure Client 4.9 | See the advisory |
| Cisco Secure Client 4.9 | See the advisory |
| Cisco Secure Client 4.9 | See the advisory |
| Cisco Secure Client 4.9 | See the advisory |
| Cisco Secure Client 4.9 | See the advisory |
| Cisco Secure Client 4.9 | See the advisory |
| Cisco Secure Client 4.9 | See the advisory |
| Cisco Secure Client 4.9 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 4.10 | See the advisory |
| Cisco Secure Client 5.0 | See the advisory |
| Cisco Secure Client 5.0 | See the advisory |
| Cisco Secure Client 5.0 | See the advisory |
| Cisco Secure Client 5.0 | See the advisory |
| Cisco Secure Client 5.0 | See the advisory |
| Cisco Secure Client 5.0 | See the advisory |
| Cisco Secure Client 5.0 | See the advisory |
| Cisco Secure Client 5.0 | See the advisory |
| Cisco Secure Client 5.0 | See the advisory |
| Cisco Secure Client 5.1 | See the advisory |
| Cisco Secure Client 5.1 | See the advisory |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Exploitation
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 11 Oct 2026.