HTTP::Daemon versions before 6.17 for Perl allow OS command injection via send_file(). send_file() opens its string argument with Perl's 2-arg open(). The 2-arg form interprets magic prefixes: '| cmd' and 'cmd |' open a pipe to a subprocess, '> path' and '>> path' open the path for write or append. Untrusted input passed to send_file() can run OS commands at the daemon process UID. The read-pipe form ('cmd |') also leaks subprocess stdout into the HTTP response body. The write-mode forms can create or truncate files at attacker chosen paths.

• https://github.com/libwww-perl/HTTP-Daemon/pull/89
• https://github.com/libwww-perl/HTTP-Daemon/commit/945d35141d94490f749640bd4390acd6a2193995.patch
• https://metacpan.org/release/OALDERS/HTTP-Daemon-6.17/changes