very insecure

SELECT * FROM gallery2 WHERE topic_id="537588" UNION SELECT * FROM gallery2 WHERE topic_id="757589" UNION SELECT * FROM gallery2 WHERE topic_id="165737" UNION SELECT * FROM gallery2 WHERE topic_id="1039011" UNION SELECT * FROM gallery2 WHERE topic_id="527115" UNION SELECT * FROM gallery2 WHERE topic_id="205737" UNION SELECT * FROM gallery2 WHERE topic_id="1540354" UNION SELECT * FROM gallery2 WHERE topic_id="93233" UNION SELECT * FROM gallery2 WHERE topic_id="1143362" UNION SELECT * FROM gallery2 WHERE topic_id="582548" UNION SELECT * FROM gallery2 WHERE topic_id="753110" UNION SELECT * FROM gallery2 WHERE topic_id="751883" UNION SELECT * FROM gallery2 WHERE topic_id="1384346" UNION SELECT * FROM gallery2 WHERE topic_id="1616964" UNION SELECT * FROM gallery2 WHERE topic_id="1499424" UNION SELECT * FROM gallery2 WHERE topic_id="1583065"