mm/mmap.c in the hugetlb kernel, when run on PowerPC systems, does not prevent stack expansion from entering into reserved kernel page memory, which allows local users to cause a denial of service (OOPS) via unspecified vectors.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11455
https://exchange.xforce.ibmcloud.com/vulnerabilities/36592
https://bugzilla.redhat.com/show_bug.cgi?id=253313
http://www.ubuntu.com/usn/usn-518-1
http://www.redhat.com/support/errata/RHSA-2007-1049.html
http://www.redhat.com/support/errata/RHSA-2007-0939.html
http://www.redhat.com/support/errata/RHSA-2007-0705.html
http://www.debian.org/security/2008/dsa-1504
http://www.debian.org/security/2007/dsa-1378
http://support.avaya.com/elmodocs2/security/ASA-2007-474.htm
http://secunia.com/advisories/29058
http://secunia.com/advisories/27913
http://secunia.com/advisories/27747
http://secunia.com/advisories/27436
http://secunia.com/advisories/26978
http://secunia.com/advisories/26955
http://secunia.com/advisories/26760