diff --git a/src/net_processing.cpp b/src/net_processing.cpp
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -3945,8 +3945,11 @@
         return;
     }
 
-    if (msg_type == NetMsgType::AVAHELLO && g_avalanche &&
-        gArgs.GetBoolArg("-enableavalanche", AVALANCHE_DEFAULT_ENABLED)) {
+    if (msg_type == NetMsgType::AVAHELLO && g_avalanche) {
+        if (!gArgs.GetBoolArg("-enableavalanche", AVALANCHE_DEFAULT_ENABLED)) {
+            Misbehaving(pfrom, 20, "unsolicited-avahello");
+            return;
+        }
         if (!pfrom.m_avalanche_state) {
             pfrom.m_avalanche_state = std::make_unique<CNode::AvalancheState>();
         }
@@ -3970,8 +3973,11 @@
 
     // Ignore avalanche requests while importing
     if (msg_type == NetMsgType::AVAPOLL && !fImporting && !fReindex &&
-        g_avalanche &&
-        gArgs.GetBoolArg("-enableavalanche", AVALANCHE_DEFAULT_ENABLED)) {
+        g_avalanche) {
+        if (!gArgs.GetBoolArg("-enableavalanche", AVALANCHE_DEFAULT_ENABLED)) {
+            Misbehaving(pfrom, 20, "unsolicited-avapoll");
+            return;
+        }
         auto now = std::chrono::steady_clock::now();
         int64_t cooldown =
             gArgs.GetArg("-avacooldown", AVALANCHE_DEFAULT_COOLDOWN);
@@ -4080,8 +4086,11 @@
 
     // Ignore avalanche requests while importing
     if (msg_type == NetMsgType::AVARESPONSE && !fImporting && !fReindex &&
-        g_avalanche &&
-        gArgs.GetBoolArg("-enableavalanche", AVALANCHE_DEFAULT_ENABLED)) {
+        g_avalanche) {
+        if (!gArgs.GetBoolArg("-enableavalanche", AVALANCHE_DEFAULT_ENABLED)) {
+            Misbehaving(pfrom, 20, "unsolicited-avaresponse");
+            return;
+        }
         // As long as QUIC is not implemented, we need to sign response and
         // verify response's signatures in order to avoid any manipulation of
         // messages at the transport level.
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
@@ -10,6 +10,9 @@
 from test_framework.messages import (
     CBlockHeader,
     CInv,
+    msg_avahello,
+    msg_avapoll,
+    msg_avaresponse,
     msg_getdata,
     msg_headers,
     msg_inv,
@@ -71,6 +74,7 @@
         self.test_addrv2_too_long_address()
         self.test_addrv2_unrecognized_network()
         self.test_large_inv()
+        self.test_unsolicited_ava_messages()
 
         node = self.nodes[0]
         self.node = node
@@ -350,6 +354,26 @@
             conn.send_and_ping(msg)
         self.nodes[0].disconnect_p2ps()
 
+    def test_unsolicited_ava_messages(self):
+        """Node 0 has avalanche disabled by default. If a node does not
+        advertise the avalanche service flag, it does not expect to receive
+        any avalanche related message and should consider it as spam.
+        """
+        conn = self.nodes[0].add_p2p_connection(P2PInterface())
+        with self.nodes[0].assert_debug_log(
+                ['Misbehaving', 'peer=9 (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']):
+            msg = msg_avapoll()
+            conn.send_and_ping(msg)
+        with self.nodes[0].assert_debug_log(
+                ['Misbehaving', 'peer=9 (40 -> 60): unsolicited-avaresponse']):
+            msg = msg_avaresponse()
+            conn.send_and_ping(msg)
+        self.nodes[0].disconnect_p2ps()
+
     def _tweak_msg_data_size(self, message, wrong_size):
         """
         Return a raw message based on another message but with an incorrect data size in
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
@@ -27,6 +27,8 @@
 import struct
 import time
 
+from typing import List
+
 from test_framework.siphash import siphash256
 from test_framework.util import hex_str_to_bytes, assert_equal
 
@@ -948,8 +950,8 @@
     __slots__ = ("proofid", "levels")
 
     def __init__(self, proofid=0, levels=None):
-        self.proofid = proofid
-        self.levels = levels
+        self.proofid: int = proofid
+        self.levels: List[AvalancheDelegationLevel] = levels or []
 
     def deserialize(self, f):
         self.proofid = deser_uint256(f)