Bugzilla before 3.2.10, 3.4.x before 3.4.10, 3.6.x before 3.6.4, and 4.0.x before 4.0rc2 creates a clickable link for a (1) javascript: or (2) data: URI in the URL (aka bug_file_loc) field, which allows remote attackers to conduct cross-site scripting (XSS) attacks against logged-out users via a crafted URI.
https://exchange.xforce.ibmcloud.com/vulnerabilities/65005
https://bugzilla.mozilla.org/show_bug.cgi?id=628034
http://www.vupen.com/english/advisories/2011/0271
http://www.vupen.com/english/advisories/2011/0207
http://www.securityfocus.com/bid/45982
http://www.debian.org/security/2011/dsa-2322
http://www.bugzilla.org/security/3.2.9/
http://secunia.com/advisories/43165
http://secunia.com/advisories/43033
http://lists.fedoraproject.org/pipermail/package-announce/2011-February/053678.html
http://lists.fedoraproject.org/pipermail/package-announce/2011-February/053665.html