In Nim before 1.2.6, the standard library asyncftpclient lacks a check for whether a message contains a newline character.
https://github.com/tintinweb/pub/tree/master/pocs/cve-2020-15690
https://github.com/nim-lang/Nim/compare/v1.2.4...v1.2.6
https://consensys.net/diligence/vulnerabilities/nim-asyncftpd-crlf-injection/