diff --git a/Lib/http/cookies.py b/Lib/http/cookies.py
index 6b9ed24ad8ec78..57791c6ab0886d 100644
--- a/Lib/http/cookies.py
+++ b/Lib/http/cookies.py
@@ -424,9 +424,11 @@ def OutputString(self, attrs=None):
     (                              # Optional group: there may not be a value.
     \s*=\s*                          # Equal Sign
     (?P<val>                         # Start of group 'val'
-    "(?:[^\\"]|\\.)*"                  # Any doublequoted string
+    "(?:[^\\"]|\\.)*"                  # Any double-quoted string
     |                                  # or
-    \w{3},\s[\w\d\s-]{9,11}\s[\d:]{8}\sGMT  # Special case for "expires" attr
+    # Special case for "expires" attr
+    (\w{3,6}day|\w{3}),\s              # Day of the week or abbreviated day
+    [\w\d\s-]{9,11}\s[\d:]{8}\sGMT     # Date and time in specific format
     |                                  # or
     [""" + _LegalValueChars + r"""]*      # Any word or empty string
     )                                # End of group 'val'
diff --git a/Lib/test/test_http_cookies.py b/Lib/test/test_http_cookies.py
index 8879902a6e2f41..7b3dc0fdaedc3b 100644
--- a/Lib/test/test_http_cookies.py
+++ b/Lib/test/test_http_cookies.py
@@ -59,6 +59,52 @@ def test_basic(self):
             for k, v in sorted(case['dict'].items()):
                 self.assertEqual(C[k].value, v)
 
+    def test_obsolete_rfc850_date_format(self):
+        # Test cases with different days and dates in obsolete RFC 850 format
+        test_cases = [
+            # from RFC 850, change EST to GMT
+            # https://datatracker.ietf.org/doc/html/rfc850#section-2
+            {
+                'data': 'key=value; expires=Saturday, 01-Jan-83 00:00:00 GMT',
+                'output': 'Saturday, 01-Jan-83 00:00:00 GMT'
+            },
+            {
+                'data': 'key=value; expires=Friday, 19-Nov-82 16:59:30 GMT',
+                'output': 'Friday, 19-Nov-82 16:59:30 GMT'
+            },
+            # from RFC 9110
+            # https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.7-6
+            {
+                'data': 'key=value; expires=Sunday, 06-Nov-94 08:49:37 GMT',
+                'output': 'Sunday, 06-Nov-94 08:49:37 GMT'
+            },
+            # other test cases
+            {
+                'data': 'key=value; expires=Wednesday, 09-Nov-94 08:49:37 GMT',
+                'output': 'Wednesday, 09-Nov-94 08:49:37 GMT'
+            },
+            {
+                'data': 'key=value; expires=Friday, 11-Nov-94 08:49:37 GMT',
+                'output': 'Friday, 11-Nov-94 08:49:37 GMT'
+            },
+            {
+                'data': 'key=value; expires=Monday, 14-Nov-94 08:49:37 GMT',
+                'output': 'Monday, 14-Nov-94 08:49:37 GMT'
+            },
+        ]
+
+        for case in test_cases:
+            with self.subTest(data=case['data']):
+                C = cookies.SimpleCookie()
+                C.load(case['data'])
+
+                # Extract the cookie name from the data string
+                cookie_name = case['data'].split('=')[0]
+
+                # Check if the cookie is loaded correctly
+                self.assertIn(cookie_name, C)
+                self.assertEqual(C[cookie_name].get('expires'), case['output'])
+
     def test_unquote(self):
         cases = [
             (r'a="b=\""', 'b="'),
diff --git a/Misc/NEWS.d/next/Library/2024-08-27-18-58-01.gh-issue-123401.t4-FpI.rst b/Misc/NEWS.d/next/Library/2024-08-27-18-58-01.gh-issue-123401.t4-FpI.rst
new file mode 100644
index 00000000000000..638f3f76239ca6
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-08-27-18-58-01.gh-issue-123401.t4-FpI.rst
@@ -0,0 +1,3 @@
+The :mod:`http.cookies` module now supports parsing obsolete :rfc:`850`
+date formats, in accordance with :rfc:`9110` requirements.
+Patch by Nano Zheng.