A client side enforcement of server side security vulnerability exists in rails < 5.2.4.2 and rails < 6.0.3.1 ActiveStorage's S3 adapter that allows the Content-Length of a direct file upload to be modified by an end user bypassing upload limits.
https://www.debian.org/security/2020/dsa-4766
https://hackerone.com/reports/789579
https://groups.google.com/g/rubyonrails-security/c/PjU3946mreQ