diff --git a/borg/remote.py b/borg/remote.py
index 5662a8dbc..5768efad6 100644
--- a/borg/remote.py
+++ b/borg/remote.py
@@ -153,6 +153,7 @@ def __init__(self, location, create=False, lock_wait=None, lock=True, args=None)
             # pyinstaller binary adds LD_LIBRARY_PATH=/tmp/_ME... but we do not want
             # that the system's ssh binary picks up (non-matching) libraries from there
             env.pop('LD_LIBRARY_PATH', None)
+        env.pop('BORG_PASSPHRASE', None)  # security: do not give secrets to subprocess
         self.p = Popen(borg_cmd, bufsize=0, stdin=PIPE, stdout=PIPE, stderr=PIPE, env=env)
         self.stdin_fd = self.p.stdin.fileno()
         self.stdout_fd = self.p.stdout.fileno()