        foreach($course_RET as $period_date)
        {
            // $period_days_append_sql .="(sp.start_time<='$period_date[END_TIME]' AND '$period_date[START_TIME]'<=sp.end_time AND IF(course_period_date IS NULL, course_period_date='$period_date[COURSE_PERIOD_DATE]',DAYS LIKE '%$period_date[DAYS]%')) OR ";
              $period_days_append_sql .="(sp.start_time<='$period_date[END_TIME]' AND '$period_date[START_TIME]'<=sp.end_time AND (cpv.course_period_date IS NULL OR cpv.course_period_date='$period_date[COURSE_PERIOD_DATE]') AND cpv.DAYS LIKE '%$period_date[DAYS]%') OR ";

        }
The software uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the software does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.