new file mode 100644
@@ -0,0 +1,135 @@
+From 4dc2cae3abd75f386374d0635d00443b897d0672 Mon Sep 17 00:00:00 2001
+From: "Miss Islington (bot)"
+ <31488909+miss-islington@users.noreply.github.com>
+Date: Wed, 22 Jun 2022 01:42:52 -0700
+Subject: [PATCH] gh-87389: Fix an open redirection vulnerability in
+ http.server. (GH-93879) (GH-94094)
+
+Fix an open redirection vulnerability in the `http.server` module when
+an URI path starts with `//` that could produce a 301 Location header
+with a misleading target. Vulnerability discovered, and logic fix
+proposed, by Hamza Avvan (@hamzaavvan).
+
+Test and comments authored by Gregory P. Smith [Google].
+(cherry picked from commit 4abab6b603dd38bec1168e9a37c40a48ec89508e)
+
+Co-authored-by: Gregory P. Smith <greg@krypto.org>
+
+Signed-off-by: Riyaz Khan <Riyaz.Khan@kpit.com>
+
+CVE: CVE-2021-28861
+
+Upstream-Status: Backport [https://github.com/python/cpython/commit/4dc2cae3abd75f386374d0635d00443b897d0672]
+
+---
+ Lib/http/server.py | 7 +++
+ Lib/test/test_httpservers.py | 53 ++++++++++++++++++-
+ ...2-06-15-20-09-23.gh-issue-87389.QVaC3f.rst | 3 ++
+ 3 files changed, 61 insertions(+), 2 deletions(-)
+ create mode 100644 Misc/NEWS.d/next/Security/2022-06-15-20-09-23.gh-issue-87389.QVaC3f.rst
+
+diff --git a/Lib/http/server.py b/Lib/http/server.py
+index 38f7accad7a3..39de35458c38 100644
+--- a/Lib/http/server.py
++++ b/Lib/http/server.py
+@@ -332,6 +332,13 @@ def parse_request(self):
+ return False
+ self.command, self.path = command, path
+
++ # gh-87389: The purpose of replacing '//' with '/' is to protect
++ # against open redirect attacks possibly triggered if the path starts
++ # with '//' because http clients treat //path as an absolute URI
++ # without scheme (similar to http://path) rather than a path.
++ if self.path.startswith('//'):
++ self.path = '/' + self.path.lstrip('/') # Reduce to a single /
++
+ # Examine the headers and look for a Connection directive.
+ try:
+ self.headers = http.client.parse_headers(self.rfile,
+diff --git a/Lib/test/test_httpservers.py b/Lib/test/test_httpservers.py
+index 87d4924a34b3..fb026188f0b4 100644
+--- a/Lib/test/test_httpservers.py
++++ b/Lib/test/test_httpservers.py
+@@ -330,7 +330,7 @@ class request_handler(NoLogRequestHandler, SimpleHTTPRequestHandler):
+ pass
+
+ def setUp(self):
+- BaseTestCase.setUp(self)
++ super().setUp()
+ self.cwd = os.getcwd()
+ basetempdir = tempfile.gettempdir()
+ os.chdir(basetempdir)
+@@ -358,7 +358,7 @@ def tearDown(self):
+ except:
+ pass
+ finally:
+- BaseTestCase.tearDown(self)
++ super().tearDown()
+
+ def check_status_and_reason(self, response, status, data=None):
+ def close_conn():
+@@ -414,6 +414,55 @@ def test_undecodable_filename(self):
+ self.check_status_and_reason(response, HTTPStatus.OK,
+ data=support.TESTFN_UNDECODABLE)
+
++ def test_get_dir_redirect_location_domain_injection_bug(self):
++ """Ensure //evil.co/..%2f../../X does not put //evil.co/ in Location.
++
++ //netloc/ in a Location header is a redirect to a new host.
++ https://github.com/python/cpython/issues/87389
++
++ This checks that a path resolving to a directory on our server cannot
++ resolve into a redirect to another server.
++ """
++ os.mkdir(os.path.join(self.tempdir, 'existing_directory'))
++ url = f'/python.org/..%2f..%2f..%2f..%2f..%2f../%0a%0d/../{self.tempdir_name}/existing_directory'
++ expected_location = f'{url}/' # /python.org.../ single slash single prefix, trailing slash
++ # Canonicalizes to /tmp/tempdir_name/existing_directory which does
++ # exist and is a dir, triggering the 301 redirect logic.
++ response = self.request(url)
++ self.check_status_and_reason(response, HTTPStatus.MOVED_PERMANENTLY)
++ location = response.getheader('Location')
++ self.assertEqual(location, expected_location, msg='non-attack failed!')
++
++ # //python.org... multi-slash prefix, no trailing slash
++ attack_url = f'/{url}'
++ response = self.request(attack_url)
++ self.check_status_and_reason(response, HTTPStatus.MOVED_PERMANENTLY)
++ location = response.getheader('Location')
++ self.assertFalse(location.startswith('//'), msg=location)
++ self.assertEqual(location, expected_location,
++ msg='Expected Location header to start with a single / and '
++ 'end with a / as this is a directory redirect.')
++
++ # ///python.org... triple-slash prefix, no trailing slash
++ attack3_url = f'//{url}'
++ response = self.request(attack3_url)
++ self.check_status_and_reason(response, HTTPStatus.MOVED_PERMANENTLY)
++ self.assertEqual(response.getheader('Location'), expected_location)
++
++ # If the second word in the http request (Request-URI for the http
++ # method) is a full URI, we don't worry about it, as that'll be parsed
++ # and reassembled as a full URI within BaseHTTPRequestHandler.send_head
++ # so no errant scheme-less //netloc//evil.co/ domain mixup can happen.
++ attack_scheme_netloc_2slash_url = f'https://pypi.org/{url}'
++ expected_scheme_netloc_location = f'{attack_scheme_netloc_2slash_url}/'
++ response = self.request(attack_scheme_netloc_2slash_url)
++ self.check_status_and_reason(response, HTTPStatus.MOVED_PERMANENTLY)
++ location = response.getheader('Location')
++ # We're just ensuring that the scheme and domain make it through, if
++ # there are or aren't multiple slashes at the start of the path that
++ # follows that isn't important in this Location: header.
++ self.assertTrue(location.startswith('https://pypi.org/'), msg=location)
++
+ def test_get(self):
+ #constructs the path relative to the root directory of the HTTPServer
+ response = self.request(self.base_url + '/test')
+diff --git a/Misc/NEWS.d/next/Security/2022-06-15-20-09-23.gh-issue-87389.QVaC3f.rst b/Misc/NEWS.d/next/Security/2022-06-15-20-09-23.gh-issue-87389.QVaC3f.rst
+new file mode 100644
+index 000000000000..029d437190de
+--- /dev/null
++++ b/Misc/NEWS.d/next/Security/2022-06-15-20-09-23.gh-issue-87389.QVaC3f.rst
+@@ -0,0 +1,3 @@
++:mod:`http.server`: Fix an open redirection vulnerability in the HTTP server
++when an URI path starts with ``//``. Vulnerability discovered, and initial
++fix proposed, by Hamza Avvan.
@@ -34,6 +34,7 @@ SRC_URI = "http://www.python.org/ftp/python/${PV}/Python-${PV}.tar.xz \
file://0001-python3-Do-not-hardcode-lib-for-distutils.patch \
file://0020-configure.ac-setup.py-do-not-add-a-curses-include-pa.patch \
file://makerace.patch \
+ file://CVE-2021-28861.patch \
"
SRC_URI_append_class-native = " \