diff --git a/mitogen/fakessh.py b/mitogen/fakessh.py
index 65861f0b..c1b52280 100644
--- a/mitogen/fakessh.py
+++ b/mitogen/fakessh.py
@@ -281,6 +281,7 @@ def _fakessh_main(mitogen_, dest_context_id):
     if not hostname:
         die('Missing hostname')
 
+    subsystem = False
     for opt, optarg in opts:
         if opt == '-s':
             subsystem = True