template/en/default/bug/field-events.js.tmpl in Bugzilla 3.x before 3.6.12, 3.7.x and 4.0.x before 4.0.9, 4.1.x and 4.2.x before 4.2.4, and 4.3.x and 4.4.x before 4.4rc1 generates JavaScript function calls containing private product names or private component names in certain circumstances involving custom-field visibility control, which allows remote attackers to obtain sensitive information by reading HTML source code.