The is a code injection vulnerability in versions of Rails prior to 5.0.1 that would allow an attacker who controlled the locals argument of a render call to perform a RCE.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-8163
• https://hackerone.com/reports/304805
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionview/CVE-2020-8163.yml
• https://groups.google.com/forum/#!topic/rubyonrails-security/hWuKcHyoKh0
• https://groups.google.com/g/rubyonrails-security/c/hWuKcHyoKh0
• https://lists.debian.org/debian-lts-announce/2020/07/msg00013.html
• http://packetstormsecurity.com/files/158604/Ruby-On-Rails-5.0.1-Remote-Code-Execution.html