Ruby Dragonfly before 1.4.0 contains an argument injection vulnerability that allows remote attackers to read and write to arbitrary files via a crafted URL when the verify_url option is disabled. This may lead to code execution. The problem occurs because the generate and process features mishandle use of the ImageMagick convert utility.
View the template here CVE-2021-33564.yaml
References:
https://github.com/markevans/dragonfly/compare/v1.3.0...v1.4.0