Public Vulnerability Reports

Multiple Vendor X Server XInput Extension Multiple Memory Corruption Vulnerabilities



The X Window System (or X11) is a graphical windowing system used on Unix-like systems. It is based on a client/server model. More information about about The X Window system is available at the following URL.


Local exploitation of multiple memory corruption vulnerabilities in the X.Org X server, as included in various vendors' operating system distributions, allows attackers to execute arbitrary code with the privileges of the X server, typically root.

Vulnerable code exists within multiple functions in the XInput extension. By sending specially crafted X11 requests, an attacker is able to corrupt heap memory located after their request data. This results in a potentially exploitable condition.


Exploitation allows an attacker to execute arbitrary code with root privileges. In order to exploit these vulnerabilities, an attacker must be able to send commands to an affected X server. This typically requires access to the console or access to the same account as a user who is on the console.

If an X Server is configured to listen for TCP based client connections, and a client is granted access to create sessions (via the xhosts file), then these vulnerabilities can be exploited remotely.


iDefense has confirmed the existence of these vulnerabilities in X.Org X11 version R7.3. Previous versions may also be affected.


iDefense is currently unaware of any workarounds for this issue. The XInput extension is normally compiled into the X Server; as such, it's not possible to disable it from being loaded in the configuration file.


The X.Org team has addressed these vulnerabilities with the release of Xserver version 1.4.1. Additionally, patches for versions 1.4 and 1.2 have been made available. For more information, consult the X.Org advisory at the following URL.


The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-6427 to this issue. This is a candidate for inclusion in the CVE list (, which standardizes names for security problems.


11/29/2007 Initial vendor notification
12/04/2007 Initial vendor response
01/17/2008 Coordinated public disclosure


These vulnerabilities were reported to VeriSign iDefense by regenrecht.

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Copyright © 2008 Verisign, Inc.

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