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Ubuntu: New X.Org packages fix security vulnerability

It was discovered that the X wrapper incorrectly checked certain console permissions when launched by unprivileged users. An attacker connected remotely could use this flaw to start X, bypassing the console permissions check. Updated packages are available from security.ubuntu.com.

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Ubuntu Security Notice USN-1349-1
January 26, 2012

xorg vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 11.10
- Ubuntu 11.04
- Ubuntu 10.10
- Ubuntu 10.04 LTS

Summary:

X could be made to start by a user who lacked appropriate permissions.

Software Description:
- xorg: X.Org X Window System

Details:

It was discovered that the X wrapper incorrectly checked certain console
permissions when launched by unprivileged users. An attacker connected
remotely could use this flaw to start X, bypassing the console permissions
check.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 11.10:
 xserver-xorg                    1:7.6+7ubuntu7.1

Ubuntu 11.04:
 xserver-xorg                    1:7.6+4ubuntu3.2

Ubuntu 10.10:
 xserver-xorg                    1:7.5+6ubuntu3.1

Ubuntu 10.04 LTS:
 xserver-xorg                    1:7.5+5ubuntu1.1

In general, a standard system update will make all the necessary changes.

References:
 http://www.ubuntu.com/usn/usn-1349-1
 CVE-2011-4613

Package Information:
 https://launchpad.net/ubuntu/+source/xorg/1:7.6+7ubuntu7.1
 https://launchpad.net/ubuntu/+source/xorg/1:7.6+4ubuntu3.2
 https://launchpad.net/ubuntu/+source/xorg/1:7.5+6ubuntu3.1
 https://launchpad.net/ubuntu/+source/xorg/1:7.5+5ubuntu1.1