From 7a334cc96ee16186e26943d7777bfbefddecaf08 Mon Sep 17 00:00:00 2001
From: Nate Prewitt <nate.prewitt@gmail.com>
Date: Mon, 22 May 2023 08:08:57 -0700
Subject: [PATCH] Merge pull request from GHSA-j8r2-6x86-q33q

---
 requests/sessions.py   |  4 +++-
 tests/test_requests.py | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/requests/sessions.py b/requests/sessions.py
index e8e2d609a78d..6e73925ae937 100644
--- a/requests/sessions.py
+++ b/requests/sessions.py
@@ -306,7 +306,9 @@ class SessionRedirectMixin(object):
         except KeyError:
             username, password = None, None
 
-        if username and password:
+        # urllib3 handles proxy authorization for us in the standard adapter.
+        # Avoid appending this to TLS tunneled requests where it may be leaked.
+        if not scheme.startswith('https') and username and password:
             headers['Proxy-Authorization'] = _basic_auth_str(username, password)
 
         return new_proxies
diff --git a/tests/test_requests.py b/tests/test_requests.py
index e730f7648b4d..66ee3f5fdd41 100644
--- a/tests/test_requests.py
+++ b/tests/test_requests.py
@@ -551,6 +551,26 @@ class TestRequests:
         with pytest.raises(InvalidProxyURL):
             requests.get(httpbin(), proxies={'http': 'http:///example.com:8080'})
 
+
+    @pytest.mark.parametrize(
+        "url,has_proxy_auth",
+        (
+            ('http://example.com', True),
+            ('https://example.com', False),
+        ),
+    )
+    def test_proxy_authorization_not_appended_to_https_request(self, url, has_proxy_auth):
+        session = requests.Session()
+        proxies = {
+            'http': 'http://test:pass@localhost:8080',
+            'https': 'http://test:pass@localhost:8090',
+        }
+        req = requests.Request('GET', url)
+        prep = req.prepare()
+        session.rebuild_proxies(prep, proxies)
+
+        assert ('Proxy-Authorization' in prep.headers) is has_proxy_auth
+
     def test_basicauth_with_netrc(self, httpbin):
         auth = ('user', 'pass')
         wrong_auth = ('wronguser', 'wrongpass')
-- 
2.44.0.769.g3c40516874-goog