The Net::Ping::External extension through 0.15 for Perl does not properly sanitize arguments (e.g., invalid hostnames) containing shell metacharacters before use of backticks in External.pm, allowing for shell command injection and arbitrary command execution if untrusted input is used.
https://rt.cpan.org/Public/Bug/Display.html?id=33230
https://bugs.debian.org/881097
http://www.openwall.com/lists/oss-security/2017/11/07/4
http://matthias.sdfeu.org/devel/net-ping-external-cmd-injection.patch