Sinatra before 2.2.0 does not validate that the expanded path matches public_dir when serving static files.
github.com/rubysec/ruby-advisory-db/blob/master/gems/sinatra/CVE-2022-29970.yml
github.com/sinatra/sinatra
github.com/sinatra/sinatra/pull/1683
github.com/sinatra/sinatra/pull/1683/commits/462c3ca1db53ed3cfc394cf5948e9c948ad1c10e
github.com/skylightio/skylight-ruby/pull/294
lists.debian.org/debian-lts-announce/2022/10/msg00034.html
nvd.nist.gov/vuln/detail/CVE-2022-29970