Direct Rendering Manager (DRM) driver in Linux kernel 2.6 does not properly check the DMA lock, which could allow remote attackers or local users to cause a denial of service (X Server crash) and possibly modify the video output.
https://www.ubuntu.com/usn/usn-38-1/
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9795
https://exchange.xforce.ibmcloud.com/vulnerabilities/15972
https://bugzilla.fedora.us/show_bug.cgi?id=2336
http://www.vupen.com/english/advisories/2005/1878
http://www.redhat.com/support/errata/RHSA-2005-663.html
http://www.redhat.com/support/errata/RHSA-2005-551.html
http://www.redhat.com/support/errata/RHSA-2005-529.html