git/Documentation/RelNotes/2.7.6.txt

Git v2.7.6 Release Notes
========================

Fixes since v2.7.5
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 * A "ssh://..." URL can result in a "ssh" command line with a
   hostname that begins with a dash "-", which would cause the "ssh"
   command to instead (mis)treat it as an option.  This is now
   prevented by forbidding such a hostname (which will not be
   necessary in the real world).

 * Similarly, when GIT_PROXY_COMMAND is configured, the command is
   run with host and port that are parsed out from "ssh://..." URL;
   a poorly written GIT_PROXY_COMMAND could be tricked into treating
   a string that begins with a dash "-".  This is now prevented by
   forbidding such a hostname and port number (again, which will not
   be necessary in the real world).

 * In the same spirit, a repository name that begins with a dash "-"
   is also forbidden now.

Credits go to Brian Neel at GitLab, Joern Schneeweisz of Recurity
Labs and Jeff King at GitHub.