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.