show_bug.cgi in Bugzilla 2.17.1 through 2.18rc2 and 2.19 from CVS, when using the insidergroup feature and exporting a bug to XML, shows comments and attachment summaries which are marked as private, which allows remote attackers to gain sensitive information.
https://exchange.xforce.ibmcloud.com/vulnerabilities/17841
https://bugzilla.mozilla.org/show_bug.cgi?id=263780