Merge pull request from GHSA-34jh-p97f-mpxf

* Strip Proxy-Authorization header on redirects

* Fix test_retry_default_remove_headers_on_redirect

* Set release date

CHANGES.rst

@@ -1,3 +1,8 @@
+2.2.2 (2024-06-17)
+==================
+
+- Added the ``Proxy-Authorization`` header to the list of headers to strip from requests when redirecting to a different host. As before, different headers can be set via ``Retry.remove_headers_on_redirect``.
+
 2.2.1 (2024-02-16)
 ==================
 

src/urllib3/util/retry.py

@@ -189,7 +189,9 @@ class Retry:
     RETRY_AFTER_STATUS_CODES = frozenset([413, 429, 503])
 
     #: Default headers to be used for ``remove_headers_on_redirect``
-    DEFAULT_REMOVE_HEADERS_ON_REDIRECT = frozenset(["Cookie", "Authorization"])
+    DEFAULT_REMOVE_HEADERS_ON_REDIRECT = frozenset(
+        ["Cookie", "Authorization", "Proxy-Authorization"]
+    )
 
     #: Default maximum backoff time.
     DEFAULT_BACKOFF_MAX = 120

test/test_retry.py

@@ -334,7 +334,11 @@ def test_retry_method_not_allowed(self) -> None:
     def test_retry_default_remove_headers_on_redirect(self) -> None:
         retry = Retry()
 
-        assert retry.remove_headers_on_redirect == {"authorization", "cookie"}
+        assert retry.remove_headers_on_redirect == {
+            "authorization",
+            "proxy-authorization",
+            "cookie",
+        }
 
     def test_retry_set_remove_headers_on_redirect(self) -> None:
         retry = Retry(remove_headers_on_redirect=["X-API-Secret"])

test/with_dummyserver/test_poolmanager.py

@@ -144,21 +144,30 @@ def test_redirect_cross_host_remove_headers(self) -> None:
                 "GET",
                 f"{self.base_url}/redirect",
                 fields={"target": f"{self.base_url_alt}/headers"},
-                headers={"Authorization": "foo", "Cookie": "foo=bar"},
+                headers={
+                    "Authorization": "foo",
+                    "Proxy-Authorization": "bar",
+                    "Cookie": "foo=bar",
+                },
             )
 
             assert r.status == 200
 
             data = r.json()
 
             assert "Authorization" not in data
+            assert "Proxy-Authorization" not in data
             assert "Cookie" not in data
 
             r = http.request(
                 "GET",
                 f"{self.base_url}/redirect",
                 fields={"target": f"{self.base_url_alt}/headers"},
-                headers={"authorization": "foo", "cookie": "foo=bar"},
+                headers={
+                    "authorization": "foo",
+                    "proxy-authorization": "baz",
+                    "cookie": "foo=bar",
+                },
             )
 
             assert r.status == 200
@@ -167,6 +176,8 @@ def test_redirect_cross_host_remove_headers(self) -> None:
 
             assert "authorization" not in data
             assert "Authorization" not in data
+            assert "proxy-authorization" not in data
+            assert "Proxy-Authorization" not in data
             assert "cookie" not in data
             assert "Cookie" not in data
 
@@ -176,7 +187,11 @@ def test_redirect_cross_host_no_remove_headers(self) -> None:
                 "GET",
                 f"{self.base_url}/redirect",
                 fields={"target": f"{self.base_url_alt}/headers"},
-                headers={"Authorization": "foo", "Cookie": "foo=bar"},
+                headers={
+                    "Authorization": "foo",
+                    "Proxy-Authorization": "bar",
+                    "Cookie": "foo=bar",
+                },
                 retries=Retry(remove_headers_on_redirect=[]),
             )
 
@@ -185,6 +200,7 @@ def test_redirect_cross_host_no_remove_headers(self) -> None:
             data = r.json()
 
             assert data["Authorization"] == "foo"
+            assert data["Proxy-Authorization"] == "bar"
             assert data["Cookie"] == "foo=bar"
 
     def test_redirect_cross_host_set_removed_headers(self) -> None:
@@ -196,6 +212,7 @@ def test_redirect_cross_host_set_removed_headers(self) -> None:
                 headers={
                     "X-API-Secret": "foo",
                     "Authorization": "bar",
+                    "Proxy-Authorization": "baz",
                     "Cookie": "foo=bar",
                 },
                 retries=Retry(remove_headers_on_redirect=["X-API-Secret"]),
@@ -207,11 +224,13 @@ def test_redirect_cross_host_set_removed_headers(self) -> None:
 
             assert "X-API-Secret" not in data
             assert data["Authorization"] == "bar"
+            assert data["Proxy-Authorization"] == "baz"
             assert data["Cookie"] == "foo=bar"
 
             headers = {
                 "x-api-secret": "foo",
                 "authorization": "bar",
+                "proxy-authorization": "baz",
                 "cookie": "foo=bar",
             }
             r = http.request(
@@ -229,12 +248,14 @@ def test_redirect_cross_host_set_removed_headers(self) -> None:
             assert "x-api-secret" not in data
             assert "X-API-Secret" not in data
             assert data["Authorization"] == "bar"
+            assert data["Proxy-Authorization"] == "baz"
             assert data["Cookie"] == "foo=bar"
 
             # Ensure the header argument itself is not modified in-place.
             assert headers == {
                 "x-api-secret": "foo",
                 "authorization": "bar",
+                "proxy-authorization": "baz",
                 "cookie": "foo=bar",
             }