Buffer overflow in IBM Informix Dynamic Server (IDS) 9.40.TC7, 9.40.TC8, 10.00.TC4, and 10.00.TC5, when running on Windows, allows remote attackers to execute arbitrary code via a long username, which causes an overflow in vsprintf when displaying in the resulting error message.  NOTE: this issue is due to an incomplete fix for CVE-2006-3853.