Cisco Secure Email Gateway HTTP response splitting

Summaryinfo

A vulnerability identified as critical has been detected in Cisco Secure Email Gateway. Impacted is an unknown function of the component HTTP Handler. This manipulation causes response splitting. This vulnerability is handled as CVE-2024-20392. The attack can be initiated remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Cisco Secure Email Gateway (affected version not known). Affected by this vulnerability is some unknown functionality of the component HTTP Handler. The manipulation with an unknown input leads to a response splitting vulnerability. The CWE definition for the vulnerability is CWE-113. The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

A vulnerability in the web-based management API of Cisco AsyncOS Software for Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to conduct an HTTP response splitting attack. This vulnerability is due to insufficient input validation of some parameters that are passed to the web-based management API of the affected system. An attacker could exploit this vulnerability by persuading a user of an affected interface to click a crafted link. A successful exploit could allow the attacker to perform cross-site scripting (XSS) attacks, resulting in the execution of arbitrary script code in the browser of the targeted user, or could allow the attacker to access sensitive, browser-based information.

It is possible to read the advisory at sec.cloudapps.cisco.com. This vulnerability is known as CVE-2024-20392 since 11/08/2023. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/06/2025).

The vulnerability scanner Nessus provides a plugin with the ID 242971 (Cisco Secure Email Gateway HTTP Response Splitting XSS (cisco-sa-esa-http-split-GLrnnOwS)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (242971). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• Cisco

Name

• Secure Email Gateway

License

• commercial

Website

• Vendor: https://www.cisco.com/

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Be aware that VulDB is the high quality source for vulnerability data.

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