diff --git a/trytond/trytond/bus.py b/trytond/trytond/bus.py
index b93f16970b..938a8d3804 100644
--- a/trytond/trytond/bus.py
+++ b/trytond/trytond/bus.py
@@ -226,7 +226,7 @@ else:
 
 
 @app.route('/<string:database_name>/bus', methods=['POST'])
-@app.auth_required
+@app.session_valid
 def subscribe(request, database_name):
     if not _allow_subscribe:
         raise exceptions.NotImplemented
diff --git a/trytond/trytond/security.py b/trytond/trytond/security.py
index 6fab3e35d8..6fe0eea9f0 100644
--- a/trytond/trytond/security.py
+++ b/trytond/trytond/security.py
@@ -1,15 +1,19 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
 import datetime as dt
+import ipaddress
 import logging
 import random
 import time
+from secrets import compare_digest
 
 try:
     from http import HTTPStatus
 except ImportError:
     from http import client as HTTPStatus
 
+from sql import Table
+from sql.conditionals import Coalesce
 from werkzeug.exceptions import abort
 
 from trytond import backend
@@ -168,6 +172,33 @@ def check_timeout(dbname, user, session, context=None):
     return valid
 
 
+def check_session(dbname, user, session, remote_addr=None):
+    "Check the session without using the pool"
+    database = backend.Database(dbname)
+    now = dt.datetime.now()
+    timeout = dt.timedelta(config.getint('session', 'max_age'))
+    conn = database.get_connection(readonly=True)
+    if remote_addr:
+        ip_addr = str(ipaddress.ip_address(remote_addr))
+    else:
+        ip_addr = None
+    try:
+        ir_session = Table('ir_session')
+        cursor = conn.cursor()
+        cursor.execute(*ir_session.select(
+                Coalesce(ir_session.write_date, ir_session.create_date),
+                ir_session.key,
+                where=((ir_session.create_uid == user)
+                    & (ir_session.ip_address == ip_addr))))
+        for session_date, session_key in cursor:
+            if abs(session_date - now) < timeout:
+                if compare_digest(session_key, session):
+                    return True
+        return False
+    finally:
+        database.put_connection(conn)
+
+
 def reset(dbname, session, context):
     try:
         with Transaction().start(dbname, 0, context=context, autocommit=True):
diff --git a/trytond/trytond/wsgi.py b/trytond/trytond/wsgi.py
index 78bb547719..57ef856320 100644
--- a/trytond/trytond/wsgi.py
+++ b/trytond/trytond/wsgi.py
@@ -27,7 +27,7 @@ try:
 except ImportError:
     from werkzeug.wsgi import SharedDataMiddleware
 
-from trytond import backend
+from trytond import backend, security
 from trytond.config import config
 from trytond.protocols.jsonrpc import JSONProtocol
 from trytond.protocols.wrappers import (
@@ -41,6 +41,14 @@ __all__ = ['TrytondWSGI', 'app']
 logger = logging.getLogger(__name__)
 
 
+def _do_basic_auth(request):
+    headers = {}
+    if request.headers.get('X-Requested-With') != 'XMLHttpRequest':
+        headers['WWW-Authenticate'] = 'Basic realm="Tryton"'
+    response = Response(None, http.client.UNAUTHORIZED, headers)
+    abort(http.client.UNAUTHORIZED, response=response)
+
+
 class Base64Converter(BaseConverter):
 
     def to_python(self, value):
@@ -81,11 +89,25 @@ class TrytondWSGI(object):
             if request.user_id:
                 return func(request, *args, **kwargs)
             else:
-                headers = {}
-                if request.headers.get('X-Requested-With') != 'XMLHttpRequest':
-                    headers['WWW-Authenticate'] = 'Basic realm="Tryton"'
-                response = Response(None, http.client.UNAUTHORIZED, headers)
-                abort(http.client.UNAUTHORIZED, response=response)
+                _do_basic_auth(request)
+        return wrapper
+
+    def session_valid(self, func):
+        @wraps(func)
+        def wrapper(request, *args, **kwargs):
+            if (not request.authorization
+                    or request.authorization.type != 'session'):
+                _do_basic_auth(request)
+            userid = request.authorization.get('userid')
+            session = request.authorization.get('session')
+            dbname = request.view_args.get('database_name')
+
+            if not security.check_session(
+                    dbname, userid, session, request.remote_addr):
+                _do_basic_auth(request)
+
+            return func(request, *args, **kwargs)
+
         return wrapper
 
     def dispatch_request(self, request):