Interchange before 5.0.1 allows remote attackers to "expose the content of arbitrary variables" and read or modify sensitive SQL information via an HTTP request ending with the "__SQLUSER__" string.
https://exchange.xforce.ibmcloud.com/vulnerabilities/15670
http://www.securityfocus.com/bid/10005
http://www.icdevgroup.org/pipermail/interchange-announce/2004/000043.html
http://www.debian.org/security/2004/dsa-471