geminabox (aka Gem in a Box) before 0.13.6 has XSS, as demonstrated by uploading a gem file that has a crafted gem.homepage value in its .gemspec file.
{
"source": "CPE_RANGE",
"extracted_events": [
{
"introduced": "0"
},
{
"last_affected": "0.13.5"
}
],
"cpe": "cpe:2.3:a:geminabox_project:geminabox:*:*:*:*:*:ruby:*:*"
}