The X server could be made to crash, run programs as an administrator, or read arbitrary files.
It was discovered that the X server incorrectly handled certain malformed input. An authorized attacker could exploit this to cause the X server to crash, leading to a denial or service, or possibly execute arbitrary code with root privileges. This issue only affected Ubuntu 10.04 LTS and 10.10. (CVE-2010-4818)
18 October 2011
A security issue affects these releases of Ubuntu and its derivatives:
The X server could be made to crash, run programs as an administrator, or read arbitrary files.
It was discovered that the X server incorrectly handled certain malformed input. An authorized attacker could exploit this to cause the X server to crash, leading to a denial or service, or possibly execute arbitrary code with root privileges. This issue only affected Ubuntu 10.04 LTS and 10.10. (CVE-2010-4818)
It was discovered that the X server incorrectly handled certain malformed input. An authorized attacker could exploit this to cause the X server to crash, leading to a denial or service, or possibly read arbitrary data from the X server process. This issue only affected Ubuntu 10.04 LTS. (CVE-2010-4819)
Vladz discovered that the X server incorrectly handled lock files. A local attacker could use this flaw to determine if a file existed or not. (CVE-2011-4028)
Vladz discovered that the X server incorrectly handled setting lock file permissions. A local attacker could use this flaw to gain read permissions on arbitrary files and view sensitive information. (CVE-2011-4029)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to restart your session to make all the necessary changes.
Vulmon