CVE 2010-1146

The Linux kernel 2.6.33.2 and earlier, when a ReiserFS filesystem exists, does not restrict read or write access to the .reiserfs_priv directory, which allows local users to gain privileges by modifying (1) extended attributes or (2) ACLs, as demonstrated by deleting a file under .reiserfs_priv/xattrs/.

See the CVE page on Mitre.org for more details.