The STARTTLS implementation in ftp_parser.c in Pure-FTPd before 1.0.30 does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted FTP sessions by sending a cleartext command that is processed after TLS is in place, related to a "plaintext command injection" attack, a similar issue to CVE-2011-0411.
https://github.com/jedisct1/pure-ftpd/commit/65c4d4ad331e94661de763e9b5304d28698999c4
https://bugzilla.redhat.com/show_bug.cgi?id=683221
https://bugzilla.novell.com/show_bug.cgi?id=686590
http://www.pureftpd.org/project/pure-ftpd/news
http://secunia.com/advisories/44548
http://secunia.com/advisories/43988
http://openwall.com/lists/oss-security/2011/04/11/8
http://openwall.com/lists/oss-security/2011/04/11/7
http://openwall.com/lists/oss-security/2011/04/11/3
http://openwall.com/lists/oss-security/2011/04/11/14
http://lists.opensuse.org/opensuse-updates/2011-05/msg00029.html
http://lists.opensuse.org/opensuse-security-announce/2011-05/msg00005.html
http://archives.pureftpd.org/archives.cgi?100:mss:3910:201103:cpeojfkblajnpinkeadd
http://archives.pureftpd.org/archives.cgi?100:mss:3906:201103:cpeojfkblajnpinkeadd