diff --git a/modules/p2ptrust/p2ptrust.py b/modules/p2ptrust/p2ptrust.py
index 0f2af29075..b06dd7f6bb 100644
--- a/modules/p2ptrust/p2ptrust.py
+++ b/modules/p2ptrust/p2ptrust.py
@@ -594,7 +594,7 @@ def process_message_report(
         self.db.publish("new_blame", data)
 
     def shutdown_gracefully(self):
-        if hasattr(self, "pigeon"):
+        if hasattr(self, "pigeon") and self.pigeon is not None:
             self.pigeon.send_signal(signal.SIGINT)
         if hasattr(self, "trust_db"):
             self.trust_db.__del__()
diff --git a/tests/unit/modules/p2ptrust/test_p2ptrust.py b/tests/unit/modules/p2ptrust/test_p2ptrust.py
new file mode 100644
index 0000000000..eead4fa2cf
--- /dev/null
+++ b/tests/unit/modules/p2ptrust/test_p2ptrust.py
@@ -0,0 +1,48 @@
+# SPDX-FileCopyrightText: 2021 Sebastian Garcia <sebastian.garcia@agents.fel.cvut.cz>
+# SPDX-License-Identifier: GPL-2.0-only
+import signal
+import sys
+import types
+from unittest.mock import MagicMock, patch
+import pytest
+
+# Stub out netifaces before any project import touches it
+if "netifaces" not in sys.modules:
+    sys.modules["netifaces"] = types.ModuleType("netifaces")
+
+
+class TestShutdownGracefully:
+    """Tests for Trust.shutdown_gracefully (issue #1840)."""
+
+    def _make_trust_instance(self):
+        """Return a bare Trust instance with only the attributes we need."""
+        from modules.p2ptrust.p2ptrust import Trust
+
+        # Build a minimal object without calling __init__
+        obj = object.__new__(Trust)
+        return obj
+
+    def test_shutdown_gracefully_pigeon_none_no_exception(self):
+        """shutdown_gracefully must not raise when self.pigeon is None."""
+        trust = self._make_trust_instance()
+        trust.pigeon = None  # mirrors the state set in _configure when binary missing
+
+        # Should complete without AttributeError
+        trust.shutdown_gracefully()
+
+    def test_shutdown_gracefully_pigeon_sends_sigint(self):
+        """shutdown_gracefully sends SIGINT when pigeon process is running."""
+        trust = self._make_trust_instance()
+        mock_pigeon = MagicMock()
+        trust.pigeon = mock_pigeon
+
+        trust.shutdown_gracefully()
+
+        mock_pigeon.send_signal.assert_called_once_with(signal.SIGINT)
+
+    def test_shutdown_gracefully_no_pigeon_attr(self):
+        """shutdown_gracefully must not raise when pigeon attribute is absent."""
+        trust = self._make_trust_instance()
+        # Do NOT set trust.pigeon at all
+
+        trust.shutdown_gracefully()