The parse_arguments function in options.c in rsyncd in rsync before 3.1.3 does not prevent multiple --protect-args uses, which allows remote attackers to bypass an argument-sanitization protection mechanism.
www.securityfocus.com/bid/102803
www.securitytracker.com/id/1040276
download.samba.org/pub/rsync/src-previews/rsync-3.1.3pre1-NEWS
git.samba.org/rsync.git/?p=rsync.git%3Ba=commit%3Bh=7706303828fcde524222babb2833864a4bd09e07
lists.debian.org/debian-lts-announce/2018/01/msg00021.html
lists.debian.org/debian-lts-announce/2019/03/msg00027.html
lists.debian.org/debian-lts-announce/2021/11/msg00028.html
security.gentoo.org/glsa/201805-04
usn.ubuntu.com/3543-1/