An issue was discovered in RubyGems 2.6 and later through 3.0.2. Gem::GemcutterUtilities#with_response may output the API response to stdout as it is. Therefore, if the API side modifies the response, escape sequence injection may occur.
https://lists.debian.org/debian-lts-announce/2020/08/msg00027.html
https://hackerone.com/reports/315081
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00036.html