PT-2016-12: HTTP Header Injection in VMware vCenter Server and ESXi

Vulnerable software

vCenter Server, ESXi
Version: 6.x


Severity level

Severity level: Medium
Impact: Arbitrary HTTP header injection
Access Vector: Remote

CVSS v2:
Base Score: 5.5
Vector: (AV:N/AC:L/Au:S/C:P/I:P/A:N)

CVE: CVE-2016-5331

Software description

vCenter Server, ESXi - enterprise-level computer virtualization products.

Vulnerability description

The specialists of the Positive Research center have detected an HTTP Header Injection vulnerability in VMware vCenter Server and ESXi.

The application does not properly sanitize user input before using it in HTTP response headers that allows a malicious user to inject arbitrary headers into HTTP responses. This allows attackers to control the headers and body of the HTTP response which can be used for conducting Cross-Site Scripting (XSS) attacks and attacks on intermediate proxy servers.

How to fix

Update your software up to the latest version

Advisory status

23.10.2015 - Vendor gets vulnerability details
04.08.2016 - Vendor releases fixed version and details
11.08.2016 - Public disclosure


The vulnerability was detected by Vladimir Ivanov, Andrey Evlanin, Mikhail Stepankin, Artem Kondratenko and Arseniy Sharoglazov, Positive Research Center (Positive Technologies Company)


Reports on the vulnerabilities previously discovered by Positive Research:

About Positive Technologies

Positive Technologies is a leading provider of vulnerability assessment, compliance management and threat analysis solutions to more than 1,000 global enterprise clients. Our solutions work seamlessly across your entire business: securing applications in development; assessing your network and application vulnerabilities; assuring compliance with regulatory requirements; and blocking real-time attacks. Our commitment to clients and research has earned Positive Technologies a reputation as one of the foremost authorities on SCADA, Banking, Telecom, Web Application and ERP security, and distinction as the #1 fastest growing Security and Vulnerability Management firm in 2012, as shown in an IDC report*. To learn more about Positive Technologies please visit

*Source: IDC Worldwide Security and Vulnerability Management 2013-2017 Forecast and 2012 Vendor Shares, doc #242465, August 2013. Based on year-over-year revenue growth in 2012 for vendors with revenues of $20M+