Bugzilla 2.10 through 2.18, 2.19.1, and 2.19.2 displays a different error message depending on whether a product exists or not, which allows remote attackers to determine hidden products.
distro.conectiva.com.br/atualizacoes/index.php?id=a&anuncio=001040
marc.info/?l=bugtraq&m=111592031902962&w=2
secunia.com/advisories/15338
www.bugzilla.org/security/2.16.8/
www.osvdb.org/16425
www.securityfocus.com/bid/13606
www.vupen.com/english/advisories/2005/0533
bugzilla.mozilla.org/show_bug.cgi?id=287109