This is a set of PHP routines to make sure that untrusted HTML code is safe to display in a end-user's browser. This filter was originally developed for SquirrelMail, but now has a life of its own, as it is used widely outside the initial project.
Htmlfilter was written and is currently maintained by Konstantin Riabitsev <icon.[at].linux.duke.edu>.
Please use the bugzilla to report a bug or an overlooked vulnerability. Choose "htmlfilter" as the name of the component.
This software is copyright © 2002-2005 by Duke University. It is available to you under the terms of GNU LGPL.
This is a library, so check out the comments in htmlfilter.inc and ponder the example code in samplefilter.php (which is a blacklist-based filter that attempts to prevent attacks and mostly succeeds. I say "mostly" because you never know what they may think of next).
Current version is htmlfilter-1.1.2 (diff to htmlfilter-1.1.1).
Test the current version and see if you find any problems [htmlfilter.inc, samplefilter.php]