source: https://www.securityfocus.com/bid/26610/info

ht://Dig is prone to a cross-site scripting vulnerability because it fails to sufficiently sanitize user-supplied data.

Exploiting this issue allows an attacker to execute arbitrary HTML or script code in a user's browser session in the context of an affected site. This may allow the attacker to steal cookie-based authentication credentials and launch other attacks.

This issue affects ht://Dig 3.2.0b6; other versions may also be vulnerable. 

http://www.example.com/cgi-bin/htsearch?config=&restrict=&exclude=&method=and&format=builtin-long&sort=<script>alert("foo")</script>&words=foo