The Execute method in the ADODB.Connection 2.7 and 2.8 ActiveX control objects (ADODB.Connection.2.7 and ADODB.Connection.2.8) in the Microsoft Data Access Components (MDAC) 2.5 SP3, 2.7 SP1, 2.8, and 2.8 SP1 does not properly track freed memory when the second argument is a BSTR, which allows remote attackers to cause a denial of service (Internet Explorer crash) and possibly execute arbitrary code via certain strings in the second and third arguments.