diff --git a/test/functional/p2p_invalid_messages.py b/test/functional/p2p_invalid_messages.py
--- a/test/functional/p2p_invalid_messages.py
+++ b/test/functional/p2p_invalid_messages.py
@@ -26,7 +26,11 @@
     P2PInterface,
 )
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import hex_str_to_bytes
+from test_framework.util import (
+    hex_str_to_bytes,
+    assert_equal,
+    wait_until,
+)
 
 
 class msg_unrecognized:
@@ -65,6 +69,7 @@
         2. Send a few messages with an incorrect data size in the header, ensure the
            messages are ignored.
         """
+        self.test_buffer()
         self.test_magic_bytes()
         self.test_checksum()
         self.test_size()
@@ -171,6 +176,28 @@
         # Node is still up.
         conn = node.add_p2p_connection(P2PDataStore())
 
+    def test_buffer(self):
+        self.log.info(
+            "Test message with header split across two buffers, should be received")
+        conn = self.nodes[0].add_p2p_connection(P2PDataStore())
+        # Create valid message
+        msg = conn.build_message(msg_ping(nonce=12345))
+        cut_pos = 12    # Chosen at an arbitrary position within the header
+        # Send message in two pieces
+        before = int(self.nodes[0].getnettotals()['totalbytesrecv'])
+        conn.send_raw_message(msg[:cut_pos])
+        # Wait until node has processed the first half of the message
+        wait_until(
+            lambda: int(
+                self.nodes[0].getnettotals()['totalbytesrecv']) != before)
+        middle = int(self.nodes[0].getnettotals()['totalbytesrecv'])
+        # If this assert fails, we've hit an unlikely race
+        # where the test framework sent a message in between the two halves
+        assert_equal(middle, before + cut_pos)
+        conn.send_raw_message(msg[cut_pos:])
+        conn.sync_with_ping(timeout=1)
+        self.nodes[0].disconnect_p2ps()
+
     def test_magic_bytes(self):
         conn = self.nodes[0].add_p2p_connection(P2PDataStore())
 
@@ -343,13 +370,13 @@
 
     def test_large_inv(self):
         conn = self.nodes[0].add_p2p_connection(P2PInterface())
-        with self.nodes[0].assert_debug_log(['Misbehaving', 'peer=8 (0 -> 20): oversized-inv: message inv size() = 50001']):
+        with self.nodes[0].assert_debug_log(['Misbehaving', '(0 -> 20): oversized-inv: message inv size() = 50001']):
             msg = msg_inv([CInv(MSG_TX, 1)] * 50001)
             conn.send_and_ping(msg)
-        with self.nodes[0].assert_debug_log(['Misbehaving', 'peer=8 (20 -> 40): too-many-inv: message getdata size() = 50001']):
+        with self.nodes[0].assert_debug_log(['Misbehaving', '(20 -> 40): too-many-inv: message getdata size() = 50001']):
             msg = msg_getdata([CInv(MSG_TX, 1)] * 50001)
             conn.send_and_ping(msg)
-        with self.nodes[0].assert_debug_log(['Misbehaving', 'peer=8 (40 -> 60): too-many-headers: headers message size = 2001']):
+        with self.nodes[0].assert_debug_log(['Misbehaving', '(40 -> 60): too-many-headers: headers message size = 2001']):
             msg = msg_headers([CBlockHeader()] * 2001)
             conn.send_and_ping(msg)
         self.nodes[0].disconnect_p2ps()
@@ -361,15 +388,15 @@
         """
         conn = self.nodes[0].add_p2p_connection(P2PInterface())
         with self.nodes[0].assert_debug_log(
-                ['Misbehaving', 'peer=9 (0 -> 20): unsolicited-avahello']):
+                ['Misbehaving', '(0 -> 20): unsolicited-avahello']):
             msg = msg_avahello()
             conn.send_and_ping(msg)
         with self.nodes[0].assert_debug_log(
-                ['Misbehaving', 'peer=9 (20 -> 40): unsolicited-avapoll']):
+                ['Misbehaving', '(20 -> 40): unsolicited-avapoll']):
             msg = msg_avapoll()
             conn.send_and_ping(msg)
         with self.nodes[0].assert_debug_log(
-                ['Misbehaving', 'peer=9 (40 -> 60): unsolicited-avaresponse']):
+                ['Misbehaving', '(40 -> 60): unsolicited-avaresponse']):
             msg = msg_avaresponse()
             conn.send_and_ping(msg)
         self.nodes[0].disconnect_p2ps()