diff --git a/CHANGES b/CHANGES
index 294829ff..2cb24c20 100644
--- a/CHANGES
+++ b/CHANGES
@@ -148,6 +148,14 @@ Major release, unreleased
 .. _#2436: https://github.com/pallets/flask/pull/2436
 .. _#2450: https://github.com/pallets/flask/pull/2450
 
+Version 0.12.3
+--------------
+
+Bugfix release, unreleased
+
+- Fix a ValueError caused by invalid Range requests in some cases
+
+
 Version 0.12.2
 --------------
 
diff --git a/flask/helpers.py b/flask/helpers.py
index efec454c..f1011ad0 100644
--- a/flask/helpers.py
+++ b/flask/helpers.py
@@ -610,7 +610,8 @@ def send_file(filename_or_fp, mimetype=None, as_attachment=False,
                 rv = rv.make_conditional(request, accept_ranges=True,
                                          complete_length=fsize)
             except RequestedRangeNotSatisfiable:
-                file.close()
+                if file is not None:
+                    file.close()
                 raise
         else:
             rv = rv.make_conditional(request)
diff --git a/tests/test_helpers.py b/tests/test_helpers.py
index cc480c26..066f3687 100644
--- a/tests/test_helpers.py
+++ b/tests/test_helpers.py
@@ -506,7 +506,7 @@ class TestSendfile(object):
 
     @pytest.mark.skipif(
         not callable(getattr(Range, 'to_content_range_header', None)),
-        reason="not implement within werkzeug"
+        reason="not implemented within werkzeug"
     )
     def test_send_file_range_request(self, app, client):
         @app.route('/')
@@ -563,7 +563,28 @@ class TestSendfile(object):
         assert rv.status_code == 200
         rv.close()
 
+    @pytest.mark.skipif(
+        not callable(getattr(Range, 'to_content_range_header', None)),
+        reason="not implemented within werkzeug"
+    )
+    def test_send_file_range_request_xsendfile_invalid(self, app, client):
+        # https://github.com/pallets/flask/issues/2526
+        app.use_x_sendfile = True
+
+        rv = client.get('/', headers={'Range': 'bytes=1000-'})
+        assert rv.status_code == 416
+        rv.close()
+
     def test_attachment(self, app, req_ctx):
+        app = flask.Flask(__name__)
+        with app.test_request_context():
+            with open(os.path.join(app.root_path, 'static/index.html')) as f:
+                rv = flask.send_file(f, as_attachment=True,
+                                     attachment_filename='index.html')
+                value, options = \
+                    parse_options_header(rv.headers['Content-Disposition'])
+                assert value == 'attachment'
+                rv.close()
 
         with open(os.path.join(app.root_path, 'static/index.html')) as f:
             rv = flask.send_file(f, as_attachment=True,