The (1) real_lookup and (2) __lookup_hash functions in fs/namei.c in the vfs implementation in the Linux kernel before 2.6.25.15 do not prevent creation of a child dentry for a deleted (aka S_DEAD) directory, which allows local users to cause a denial of service ("overflow" of the UBIFS orphan area) via a series of attempted file creations within deleted directories.
http://lists.opensuse.org/opensuse-security-announce/2008-10/msg00001.html
http://lists.opensuse.org/opensuse-security-announce/2008-10/msg00003.html
https://bugzilla.redhat.com/show_bug.cgi?id=457858
https://exchange.xforce.ibmcloud.com/vulnerabilities/44410
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10744
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6551
http://www.debian.org/security/2008/dsa-1630