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.
git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=d70b67c8bc72ee23b55381bd6a884f4796692f77
kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.25.15
lists.opensuse.org/opensuse-security-announce/2008-10/msg00001.html
lists.opensuse.org/opensuse-security-announce/2008-10/msg00003.html
lkml.org/lkml/2008/7/2/83
secunia.com/advisories/31551
secunia.com/advisories/31614
secunia.com/advisories/31836
secunia.com/advisories/31881
secunia.com/advisories/32023
secunia.com/advisories/32104
secunia.com/advisories/32190
secunia.com/advisories/32344
secunia.com/advisories/33201
secunia.com/advisories/33280
secunia.com/advisories/33556
www.debian.org/security/2008/dsa-1630
www.debian.org/security/2008/dsa-1636
www.mandriva.com/security/advisories?name=MDVSA-2008:220
www.redhat.com/support/errata/RHSA-2008-0787.html
www.redhat.com/support/errata/RHSA-2008-0857.html
www.redhat.com/support/errata/RHSA-2008-0885.html
www.redhat.com/support/errata/RHSA-2008-0973.html
www.redhat.com/support/errata/RHSA-2009-0014.html
www.securityfocus.com/bid/30647
www.securitytracker.com/id?1020739
www.vupen.com/english/advisories/2008/2430
bugzilla.redhat.com/show_bug.cgi?id=457858
exchange.xforce.ibmcloud.com/vulnerabilities/44410
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10744
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6551
usn.ubuntu.com/637-1/