Cross-site scripting (XSS) vulnerability in show_bug.cgi in Bugzilla before 3.6.13, 3.7.x and 4.0.x before 4.0.10, 4.1.x and 4.2.x before 4.2.5, and 4.3.x and 4.4.x before 4.4rc2 allows remote attackers to inject arbitrary web script or HTML via the id parameter in conjunction with an invalid value of the format parameter.