diff --git a/CHANGES.rst b/CHANGES.rst
index 92e11e2a..73b5eb98 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -92,6 +92,8 @@ Unreleased
 -   The key information for ``BadRequestKeyError`` is no longer cleared
     outside debug mode, so error handlers can still access it. This
     requires upgrading to Werkzeug 0.15.5. :issue:`3249`
+-   ``send_file`` url quotes the ":" and "/" characters for more
+    compatible UTF-8 filename support in some browsers. :issue:`3074`
 
 
 Version 1.0.3
diff --git a/README.rst b/README.rst
index 29aa8a90..6e574323 100644
--- a/README.rst
+++ b/README.rst
@@ -71,7 +71,7 @@ Links
 * Releases: https://pypi.org/project/Flask/
 * Code: https://github.com/pallets/flask
 * Issue tracker: https://github.com/pallets/flask/issues
-* Test status: https://dev.azure.com/pallets/pallets/_build?definitionId=2
+* Test status: https://dev.azure.com/pallets/flask/_build
 * Official chat: https://discord.gg/t6rrQZH
 
 .. _WSGI: https://wsgi.readthedocs.io
diff --git a/src/flask/helpers.py b/src/flask/helpers.py
index 1ae54816..b121d040 100644
--- a/src/flask/helpers.py
+++ b/src/flask/helpers.py
@@ -610,7 +610,7 @@ def send_file(
                 "filename": unicodedata.normalize("NFKD", attachment_filename).encode(
                     "ascii", "ignore"
                 ),
-                "filename*": "UTF-8''%s" % url_quote(attachment_filename),
+                'filename*': "UTF-8''%s" % url_quote(attachment_filename, safe=b""),
             }
         else:
             filenames = {"filename": attachment_filename}
diff --git a/tests/test_helpers.py b/tests/test_helpers.py
index 01fb4c34..3d4b2782 100644
--- a/tests/test_helpers.py
+++ b/tests/test_helpers.py
@@ -697,6 +697,8 @@ class TestSendfile(object):
             (u"Vögel.txt", "Vogel.txt", "V%C3%B6gel.txt"),
             # Native string not marked as Unicode on Python 2
             ("tést.txt", "test.txt", "t%C3%A9st.txt"),
+            # ":/" are not safe in filename* value
+            (u"те:/ст", '":/"', "%D1%82%D0%B5%3A%2F%D1%81%D1%82"),
         ),
     )
     def test_attachment_filename_encoding(self, filename, ascii, utf8):