Bugzilla before 2.14.1 allows remote attackers to (1) spoof a user comment via an HTTP request to process_bug.cgi using the "who" parameter, instead of the Bugzilla_login cookie, or (2) post a bug as another user by modifying the reporter parameter to enter_bug.cgi, which is passed to post_bug.cgi.
http://www.securityfocus.com/bid/3794
http://www.securityfocus.com/bid/3793
http://www.iss.net/security_center/static/7805.php
http://www.iss.net/security_center/static/7804.php
http://www.bugzilla.org/security2_14_1.html
http://rhn.redhat.com/errata/RHSA-2002-001.html
http://bugzilla.mozilla.org/show_bug.cgi?id=108516
http://bugzilla.mozilla.org/show_bug.cgi?id=108385
http://archives.neohapsis.com/archives/bugtraq/2002-01/0034.html