From the changelog of not yet released versions of MySQL:
Important Change: Partitioning: Security Fix: It was possible, by creating a
partitioned table using the DATA DIRECTORY and INDEX DIRECTORY options to gain
privileges on other tables having the same name as the partitioned table. As a
result of this fix, any table-level DATA DIRECTORY or INDEX DIRECTORY options
are now ignored for partitioned tables. (Bug#32091, CVE-2007-5970)
Referenced MySQL bug report is not public at the moment:
MySQL 5.1.x before 5.1.23 and 6.0.x before 6.0.4 allows remote
authenticated users to gain privileges on arbitrary tables via
unspecified vectors involving use of table-level DATA DIRECTORY and
INDEX DIRECTORY options when creating a partitioned table with the
same name as a table on which the user lacks privileges.
Upstream bug report remains private.
This issue did not affect mysql packages as shipped in Red Hat Enterprise Linux
2.1, 3, 4, and 5, Red Hat Application Stack v1 and v2 and Fedora, as versions
shipped do not support table partitioning. Partitioning feature was introduced
in development MySQL version 5.1.