CarrierWave is a solution for file uploads for Rails, Sinatra and other Ruby web frameworks. CarrierWave has a Content-Type allowlist bypass vulnerability, possibly leading to XSS. The validation in `allowlisted_content_type?` determines Content-Type permissions by performing a partial match. If the `content_type` argument of `allowlisted_content_type?` is passed a value crafted by the attacker, Content-Types not included in the `content_type_allowlist` will be allowed. This issue has been patched in versions 2.2.5 and 3.0.5.