diff -r 55681baf4cf9 -r 173ecccb9ee7 mercurial/subrepo.py
--- a/mercurial/subrepo.py	Mon Jul 31 16:04:44 2017 -0700
+++ b/mercurial/subrepo.py	Mon Jul 31 16:44:17 2017 -0700
@@ -1274,6 +1274,10 @@
         # The revision must be specified at the end of the URL to properly
         # update to a directory which has since been deleted and recreated.
         args.append('%s@%s' % (state[0], state[1]))
+
+        # SEC: check that the ssh url is safe
+        util.checksafessh(state[0])
+
         status, err = self._svncommand(args, failok=True)
         _sanitize(self.ui, self.wvfs, '.svn')
         if not re.search('Checked out revision [0-9]+.', status):