diff --git a/test/functional/p2p_leak_tx.py b/test/functional/p2p_leak_tx.py
new file mode 100755
--- /dev/null
+++ b/test/functional/p2p_leak_tx.py
@@ -0,0 +1,69 @@
+#!/usr/bin/env python3
+# Copyright (c) 2017-2018 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Test that we don't leak txs to inbound peers that we haven't yet announced to"""
+
+from test_framework.messages import msg_getdata, CInv
+from test_framework.mininode import P2PDataStore, network_thread_start
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import (
+    assert_equal,
+)
+
+
+class P2PNode(P2PDataStore):
+    def on_inv(self, msg):
+        pass
+
+
+class P2PLeakTxTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_wallet()
+
+    def run_test(self):
+        # The block and tx generating node
+        gen_node = self.nodes[0]
+        gen_node.generate(1)
+
+        # An "attacking" inbound peer
+        inbound_peer = self.nodes[0].add_p2p_connection(P2PNode())
+        # Backport note: the following two lines were backported out of order,
+        # and should be removed in the appropriate future backports that do a
+        # blanket removal of each of these calls across many tests.
+        network_thread_start()
+        self.nodes[0].p2p.wait_for_verack()
+
+        MAX_REPEATS = 100
+        self.log.info("Running test up to {} times.".format(MAX_REPEATS))
+        for i in range(MAX_REPEATS):
+            self.log.info('Run repeat {}'.format(i + 1))
+            txid = gen_node.sendtoaddress(gen_node.getnewaddress(), 0.01)
+
+            want_tx = msg_getdata()
+            want_tx.inv.append(CInv(t=1, h=int(txid, 16)))
+            inbound_peer.last_message.pop('notfound', None)
+            inbound_peer.send_message(want_tx)
+            inbound_peer.sync_with_ping()
+
+            if inbound_peer.last_message.get('notfound'):
+                self.log.debug(
+                    'tx {} was not yet announced to us.'.format(txid))
+                self.log.debug(
+                    "node has responded with a notfound message. End test.")
+                assert_equal(
+                    inbound_peer.last_message['notfound'].vec[0].hash, int(txid, 16))
+                inbound_peer.last_message.pop('notfound')
+                break
+            else:
+                self.log.debug(
+                    'tx {} was already announced to us. Try test again.'.format(txid))
+                assert int(txid, 16) in [
+                    inv.hash for inv in inbound_peer.last_message['inv'].inv]
+
+
+if __name__ == '__main__':
+    P2PLeakTxTest().main()
diff --git a/test/functional/test_framework/messages.py b/test/functional/test_framework/messages.py
--- a/test/functional/test_framework/messages.py
+++ b/test/functional/test_framework/messages.py
@@ -1112,6 +1112,23 @@
         return "msg_mempool()"
 
 
+class msg_notfound:
+    __slots__ = ("vec", )
+    command = b"notfound"
+
+    def __init__(self, vec=None):
+        self.vec = vec or []
+
+    def deserialize(self, f):
+        self.vec = deser_vector(f, CInv)
+
+    def serialize(self):
+        return ser_vector(self.vec)
+
+    def __repr__(self):
+        return "msg_notfound(vec={})".format(repr(self.vec))
+
+
 class msg_sendheaders:
     __slots__ = ()
     command = b"sendheaders"
diff --git a/test/functional/test_framework/mininode.py b/test/functional/test_framework/mininode.py
--- a/test/functional/test_framework/mininode.py
+++ b/test/functional/test_framework/mininode.py
@@ -39,6 +39,7 @@
     msg_headers,
     msg_inv,
     msg_mempool,
+    msg_notfound,
     msg_ping,
     msg_pong,
     msg_reject,
@@ -71,6 +72,7 @@
     b"headers": msg_headers,
     b"inv": msg_inv,
     b"mempool": msg_mempool,
+    b"notfound": msg_notfound,
     b"ping": msg_ping,
     b"pong": msg_pong,
     b"reject": msg_reject,
@@ -389,6 +391,8 @@
 
     def on_mempool(self, message): pass
 
+    def on_notfound(self, message): pass
+
     def on_pong(self, message): pass
 
     def on_reject(self, message): pass