diff --git a/addons/web_editor/controllers/main.py b/addons/web_editor/controllers/main.py
index adad212bd87..db7bab818e8 100644
--- a/addons/web_editor/controllers/main.py
+++ b/addons/web_editor/controllers/main.py
@@ -199,10 +199,11 @@ class Web_Editor(http.Controller):
 
     @http.route('/web_editor/attachment/add_data', type='json', auth='user', methods=['POST'], website=True)
     def add_data(self, name, data, is_image, quality=0, width=0, height=0, res_id=False, res_model='ir.ui.view', **kwargs):
+        data = b64decode(data)
         if is_image:
             format_error_msg = _("Uploaded image's format is not supported. Try with: %s", ', '.join(SUPPORTED_IMAGE_EXTENSIONS))
             try:
-                data = tools.image_process(b64decode(data), size=(width, height), quality=quality, verify_resolution=True)
+                data = tools.image_process(data, size=(width, height), quality=quality, verify_resolution=True)
                 mimetype = guess_mimetype(data)
                 if mimetype not in SUPPORTED_IMAGE_MIMETYPES:
                     return {'error': format_error_msg}
diff --git a/addons/web_editor/tests/__init__.py b/addons/web_editor/tests/__init__.py
index 8b3c5e99c8b..cad4102a2d7 100644
--- a/addons/web_editor/tests/__init__.py
+++ b/addons/web_editor/tests/__init__.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+from . import test_controller
 from . import test_converter
 from . import test_odoo_editor
 from . import test_views
diff --git a/addons/web_editor/tests/test_controller.py b/addons/web_editor/tests/test_controller.py
new file mode 100644
index 00000000000..a2188bf29b4
--- /dev/null
+++ b/addons/web_editor/tests/test_controller.py
@@ -0,0 +1,32 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo.tools.json import scriptsafe as json_safe
+
+import odoo.tests
+from odoo.tests.common import HttpCase
+
+
+@odoo.tests.tagged('-at_install', 'post_install')
+class TestController(HttpCase):
+    def test_01_upload_document(self):
+        self.authenticate('admin', 'admin')
+        # Upload document.
+        response = self.url_open(
+            '/web_editor/attachment/add_data',
+            headers={'Content-Type': 'application/json'},
+            data=json_safe.dumps({'params': {
+                'name': 'test.txt',
+                'data': 'SGVsbG8gd29ybGQ=',  # base64 Hello world
+                'is_image': False,
+            }})
+        ).json()
+        self.assertFalse('error' in response, 'Upload failed: %s' % response.get('error', {}).get('message'))
+        attachment_id = response['result']['id']
+        checksum = response['result']['checksum']
+        # Download document and check content.
+        response = self.url_open(
+            '/web/content/%s?unique=%s&download=true' % (attachment_id, checksum)
+        )
+        self.assertEqual(200, response.status_code, 'Expect response')
+        self.assertEqual(b'Hello world', response.content, 'Expect raw content')