diff --git a/nova/cmd/manage.py b/nova/cmd/manage.py
index 9e4e74151e82..00856c3637d4 100644
--- a/nova/cmd/manage.py
+++ b/nova/cmd/manage.py
@@ -70,6 +70,7 @@ from oslo_utils import uuidutils
 import prettytable
 
 import six.moves.urllib.parse as urlparse
+from sqlalchemy.engine import url as sqla_url
 
 from nova.api.ec2 import ec2utils
 from nova import availability_zones
@@ -1151,12 +1152,19 @@ class CellV2Commands(object):
             # based on the database connection url.
             # The cell0 database will use the same database scheme and
             # netloc as the main database, with a related path.
-            scheme, netloc, path, query, fragment = \
-                urlparse.urlsplit(CONF.database.connection)
-            root, ext = os.path.splitext(path)
-            path = root + "_cell0" + ext
-            return urlparse.urlunsplit((scheme, netloc, path, query,
-                                        fragment))
+            connection = CONF.database.connection
+            # sqlalchemy has a nice utility for parsing database connection
+            # URLs so we use that here to get the db name so we don't have to
+            # worry about parsing and splitting a URL which could have special
+            # characters in the password, which makes parsing a nightmare.
+            url = sqla_url.make_url(connection)
+            cell0_db_name = url.database + '_cell0'
+            # We need to handle multiple occurrences of the substring, e.g. if
+            # the username and db name are both 'nova' we need to only replace
+            # the last one, which is the database name in the URL, not the
+            # username.
+            connection = connection.rstrip(url.database)
+            return connection + cell0_db_name
 
         dbc = database_connection or cell0_default_connection()
         ctxt = context.RequestContext()
diff --git a/nova/tests/unit/test_nova_manage.py b/nova/tests/unit/test_nova_manage.py
index 8d8e3df882f1..d9208280009b 100644
--- a/nova/tests/unit/test_nova_manage.py
+++ b/nova/tests/unit/test_nova_manage.py
@@ -15,6 +15,7 @@
 
 import sys
 
+import ddt
 import fixtures
 import mock
 from oslo_db import exception as db_exc
@@ -809,6 +810,7 @@ class CellCommandsTestCase(test.NoDBTestCase):
         mock_db_cell_create.assert_called_once_with(ctxt, exp_values)
 
 
+@ddt.ddt
 class CellV2CommandsTestCase(test.NoDBTestCase):
     USES_DB_SELF = True
 
@@ -1138,6 +1140,29 @@ class CellV2CommandsTestCase(test.NoDBTestCase):
         self.assertEqual('fake://netloc/nova_cell0',
                          cell_mapping.database_connection)
 
+    @ddt.data('mysql+pymysql://nova:abcd0123:AB@controller/nova',
+              'mysql+pymysql://nova:abcd0123?AB@controller/nova',
+              'mysql+pymysql://nova:abcd0123@AB@controller/nova',
+              'mysql+pymysql://nova:abcd0123/AB@controller/nova',
+              'mysql+pymysql://test:abcd0123%AB@controller/nova')
+    def test_map_cell0_default_database_special_characters(self,
+                                                           decoded_connection):
+        """Tests that a URL with special characters, like in the credentials,
+        is handled properly.
+        """
+        self.flags(connection=decoded_connection, group='database')
+        ctxt = context.RequestContext()
+        self.commands.map_cell0()
+        cell_mapping = objects.CellMapping.get_by_uuid(
+            ctxt, objects.CellMapping.CELL0_UUID)
+        self.assertEqual('cell0', cell_mapping.name)
+        self.assertEqual('none:///', cell_mapping.transport_url)
+        self.assertEqual(
+            decoded_connection + '_cell0',
+            cell_mapping.database_connection)
+        # Delete the cell mapping for the next iteration.
+        cell_mapping.destroy()
+
     def _test_migrate_simple_command(self, cell0_sync_fail=False):
         ctxt = context.RequestContext()
         CONF.set_default('connection',
diff --git a/releasenotes/notes/bug-1673613-7357d40ba9ab1fa6.yaml b/releasenotes/notes/bug-1673613-7357d40ba9ab1fa6.yaml
new file mode 100644
index 000000000000..cd95df6cc2a9
--- /dev/null
+++ b/releasenotes/notes/bug-1673613-7357d40ba9ab1fa6.yaml
@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    Includes the fix for `bug 1673613`_ which could cause issues when upgrading
+    and running ``nova-manage cell_v2 simple_cell_setup`` or
+    ``nova-manage cell_v2 map_cell0`` where the database connection is read
+    from config and has special characters in the URL.
+
+    .. _bug 1673613: https://launchpad.net/bugs/1673613