fs/jfs/xattr.c in the Linux kernel before 2.6.35.2 does not properly handle a certain legacy format for storage of extended attributes, which might allow local users by bypass intended xattr namespace restrictions via an "os2." substring at the beginning of a name.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.