diff --git a/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/process.py b/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/process.py
index 6fa5be980c16..1c118d48b850 100644
--- a/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/process.py
+++ b/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/process.py
@@ -69,7 +69,9 @@ class RunKwargs(TypedDict, total=False):
 def cleanup_ssh(tmp_dir: Path) -> None:
     "Close SSH ControlMaster connection."
     for ctrl in tmp_dir.glob("ssh-*"):
-        subprocess.run(["ssh", "-o", f"ControlPath={ctrl}", "exit"], check=False)
+        subprocess.run(
+            ["ssh", "-o", f"ControlPath={ctrl}", "-O", "exit", "dummyhost"], check=False
+        )
 
 
 def run_wrapper(
diff --git a/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_process.py b/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_process.py
index 57d3865bcef4..998ad5dedc83 100644
--- a/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_process.py
+++ b/pkgs/by-name/ni/nixos-rebuild-ng/src/tests/test_process.py
@@ -1,6 +1,6 @@
 from pathlib import Path
 from typing import Any
-from unittest.mock import patch
+from unittest.mock import call, patch
 
 import nixos_rebuild.models as m
 import nixos_rebuild.process as p
@@ -8,6 +8,28 @@ import nixos_rebuild.process as p
 from .helpers import get_qualified_name
 
 
+@patch(get_qualified_name(p.subprocess.run))
+def test_cleanup_ssh(mock_run: Any, tmp_path: Path) -> None:
+    (tmp_path / "ssh-conn").touch()
+
+    p.cleanup_ssh(tmp_path)
+    mock_run.assert_has_calls(
+        [
+            call(
+                [
+                    "ssh",
+                    "-o",
+                    f"ControlPath={tmp_path}/ssh-conn",
+                    "-O",
+                    "exit",
+                    "dummyhost",
+                ],
+                check=False,
+            )
+        ]
+    )
+
+
 @patch(get_qualified_name(p.subprocess.run))
 def test_run(mock_run: Any) -> None:
     p.run_wrapper(["test", "--with", "flags"], check=True)