Multiple stack-based buffer overflows in IBM DB2 9.1 before Fixpak 5 and 9.5 before Fixpak 1 allow remote attackers to cause a denial of service (system outage) via vectors related to (1) use of XQuery to issue statements; the (2) XMLQUERY, (3) XMLEXISTS, and (4) XMLTABLE statements; and the (5) sqlrlaka function.