Oh, shoot, this needs to go into plug-security.
Sorry, go look there for the detailed info...
rc
>
> Security Advisory DW020203-PHP
> Release: 3rd February 2002
>
> PHP Safe Mode Filesystem Circumvention Problem
>
> Severity: Medium to high.
> Affects: PHP, all versions which include safe_mode feature.
> Platform: UNIX, Microsoft Windows, any platforms on which PHP is
> available.