A third party website can access information available to a user with access to a restricted bug entry using the image generation in report.cgi in all Bugzilla versions prior to 4.4.
[
{
"product": "Bugzilla",
"vendor": "Mozilla",
"versions": [
{
"status": "affected",
"version": "All versions prior to Bugzilla 4.4"
}
]
}
]