Bazaar through 2.7.0, when Subprocess SSH is used, allows remote attackers to execute arbitrary commands via a bzr+ssh URL with an initial dash character in the hostname, a related issue to CVE-2017-9800, CVE-2017-12836, CVE-2017-12976, CVE-2017-16228, CVE-2017-1000116, and CVE-2017-1000117.