diff --git a/Doc/library/urlparse.rst b/Doc/library/urlparse.rst
index 0989c88c302253..36e332c25fe00f 100644
--- a/Doc/library/urlparse.rst
+++ b/Doc/library/urlparse.rst
@@ -125,6 +125,11 @@ The :mod:`urlparse` module defines the following functions:
    decomposed before parsing, or is not a Unicode string, no error will be
    raised.
 
+   .. warning::
+
+      :func:`urlparse` does not perform validation.  See :ref:`URL parsing
+      security <url-parsing-security>` for details.
+
    .. versionchanged:: 2.5
       Added attributes to return value.
 
@@ -248,6 +253,10 @@ The :mod:`urlparse` module defines the following functions:
    decomposed before parsing, or is not a Unicode string, no error will be
    raised.
 
+   Following some of the `WHATWG spec`_ that updates RFC 3986, leading C0
+   control and space characters are stripped from the URL. ``\n``,
+   ``\r`` and tab ``\t`` characters are removed from the URL at any position.
+
    .. versionadded:: 2.2
 
    .. versionchanged:: 2.5
@@ -257,6 +266,9 @@ The :mod:`urlparse` module defines the following functions:
       Characters that affect netloc parsing under NFKC normalization will
       now raise :exc:`ValueError`.
 
+   .. versionchanged:: 2.7.17.8
+      Leading WHATWG C0 control and space characters are stripped from the URL.
+
 
 .. function:: urlunsplit(parts)
 
@@ -378,3 +390,14 @@ The following classes provide the implementations of the parse results:
 
    Concrete class for :func:`urlsplit` results.
 
+.. _url-parsing-security:
+
+URL parsing security
+--------------------
+
+The :func:`urlsplit` and :func:`urlparse` APIs do not perform **validation** of
+inputs.  They may not raise errors on inputs that other applications consider
+invalid.  They may also succeed on some inputs that might not be considered
+URLs elsewhere.  Their purpose is for practical functionality rather than
+purity.
+
diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py
index e00fb7af699668..f924289041a7a1 100644
--- a/Lib/test/test_urlparse.py
+++ b/Lib/test/test_urlparse.py
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 # Copyright (C) 2022 ActiveState Software Inc.
 # test_urlparse.py is licensed under the PSFLv2 License.
 # See the file LICENSE for details.
@@ -8,6 +9,23 @@
 import unittest
 import urlparse
 
+# Add ability to run sub-tests
+def sub_test(param_list):
+    """Decorates a test case to run it as a set of subtests."""
+
+    def decorator(f):
+
+        @functools.wraps(f)
+        def wrapped(self):
+            for param in param_list:
+                with self.subTest(**param):
+                    f(self, **param)
+
+        return wrapped
+
+    return decorator
+
+
 RFC1808_BASE = "http://a/b/c/d;p?q#f"
 RFC2396_BASE = "http://a/b/c/d;p?q"
 RFC3986_BASE = 'http://a/b/c/d;p?q'
@@ -602,16 +620,92 @@ def test_urlsplit_remove_unsafe_bytes(self):
         self.assertEqual(p.port, None)
         self.assertEqual(p.geturl(), u"http://www.python.org/javascript:alert('msg')/#frag")
 
+    def test_urlsplit_strip_url(self):
+        noise = bytes(bytearray(range(0, 0x20 + 1)))
+        base_url = "http://User:Pass@www.python.org:080/doc/?query=yes#frag"
 
-    def test_attributes_bad_port(self):
-        """Check handling of non-integer ports."""
-        p = urlparse.urlsplit("http://www.example.net:foo")
-        self.assertEqual(p.netloc, "www.example.net:foo")
-        self.assertRaises(ValueError, lambda: p.port)
+        url = noise.decode("utf-8") + base_url
+        p = urlparse.urlsplit(url)
+        self.assertEqual(p.scheme, "http")
+        self.assertEqual(p.netloc, "User:Pass@www.python.org:080")
+        self.assertEqual(p.path, "/doc/")
+        self.assertEqual(p.query, "query=yes")
+        self.assertEqual(p.fragment, "frag")
+        self.assertEqual(p.username, "User")
+        self.assertEqual(p.password, "Pass")
+        self.assertEqual(p.hostname, "www.python.org")
+        self.assertEqual(p.port, 80)
+        self.assertEqual(p.geturl(), base_url)
 
-        p = urlparse.urlparse("http://www.example.net:foo")
-        self.assertEqual(p.netloc, "www.example.net:foo")
-        self.assertRaises(ValueError, lambda: p.port)
+        url = noise + base_url.encode("utf-8")
+        p = urlparse.urlsplit(url)
+        self.assertEqual(p.scheme, b"http")
+        self.assertEqual(p.netloc, b"User:Pass@www.python.org:080")
+        self.assertEqual(p.path, b"/doc/")
+        self.assertEqual(p.query, b"query=yes")
+        self.assertEqual(p.fragment, b"frag")
+        self.assertEqual(p.username, b"User")
+        self.assertEqual(p.password, b"Pass")
+        self.assertEqual(p.hostname, b"www.python.org")
+        self.assertEqual(p.port, 80)
+        self.assertEqual(p.geturl(), base_url.encode("utf-8"))
+
+        # Test that trailing space is preserved as some applications rely on
+        # this within query strings.
+        query_spaces_url = "https://www.python.org:88/doc/?query=    "
+        p = urlparse.urlsplit(noise.decode("utf-8") + query_spaces_url)
+        self.assertEqual(p.scheme, "https")
+        self.assertEqual(p.netloc, "www.python.org:88")
+        self.assertEqual(p.path, "/doc/")
+        self.assertEqual(p.query, "query=    ")
+        self.assertEqual(p.port, 88)
+        self.assertEqual(p.geturl(), query_spaces_url)
+
+        p = urlparse.urlsplit("www.pypi.org ")
+        # That "hostname" gets considered a "path" due to the
+        # trailing space and our existing logic...  YUCK...
+        # and re-assembles via geturl aka unurlsplit into the original.
+        # django.core.validators.URLValidator (at least through v3.2) relies on
+        # this, for better or worse, to catch it in a ValidationError via its
+        # regular expressions.
+        # Here we test the basic round trip concept of such a trailing space.
+        self.assertEqual(urlparse.urlunsplit(p), "www.pypi.org ")
+
+        # with scheme as cache-key
+        url = "//www.python.org/"
+        scheme = noise.decode("utf-8") + "https" + noise.decode("utf-8")
+        for _ in range(2):
+            p = urlparse.urlsplit(url, scheme=scheme)
+            self.assertEqual(p.scheme, "https")
+            self.assertEqual(p.geturl(), "https://www.python.org/")
+
+    def test_attributes_bad_port_a(self):
+        """Check handling of invalid ports."""
+        for bytes in (False, True):
+            for parse in (urlparse.urlsplit, urlparse.urlparse):
+                # Spaces and invalid characters are stripped now, so the missing one's can't cause issues
+                # for port in ("foo", "1.5", "-1", "0x10", "-0", "1_1", " 1", "1 ", "६"):
+                for port in ("foo", "1.5",  "0x10",  "1_1"):
+                    netloc = "www.example.net:" + port
+                    url = "http://" + netloc + "/"
+                    if bytes:
+                        netloc = netloc.encode("ascii")
+                        url = url.encode("ascii")
+                    p = parse(url)
+                    self.assertEqual(p.netloc, netloc)
+                    with self.assertRaises(ValueError):
+                        p.port
+
+    def test_attributes_bad_port_b(self):
+        """Check handling of invalid ports."""
+        for parse in (urlparse.urlsplit, urlparse.urlparse):
+            for port in ("६"):
+                netloc = "www.example.net:" + port
+                url = "http://" + netloc + "/"
+                p = parse(url)
+                self.assertEqual(p.netloc, netloc)
+                with self.assertRaises(ValueError):
+                    p.port
 
     def test_attributes_without_netloc(self):
         # This example is straight from RFC 3261.  It looks like it
diff --git a/Lib/urlparse.py b/Lib/urlparse.py
index 914ccd2c6942e6..0f12940c3dc0ed 100644
--- a/Lib/urlparse.py
+++ b/Lib/urlparse.py
@@ -30,6 +30,9 @@
 parsing quirks from older RFCs are retained. The testcases in
 test_urlparse.py provides a good indicator of parsing behavior.
 
+The WHATWG URL Parser spec should also be considered.  We are not compliant with
+it either due to existing user code API behavior expectations (Hyrum's Law).
+It serves as a useful guide when making changes.
 """
 
 import re
@@ -66,6 +69,10 @@
                 '0123456789'
                 '+-.')
 
+# Leading and trailing C0 control and space to be stripped per WHATWG spec.
+# == "".join([chr(i) for i in range(0, 0x20 + 1)])
+_WHATWG_C0_CONTROL_OR_SPACE = '\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f '
+
 # Unsafe bytes to be removed per WHATWG spec
 _UNSAFE_URL_BYTES_TO_REMOVE = ['\t', '\r', '\n']
 
@@ -197,6 +204,7 @@ def urlsplit(url, scheme='', allow_fragments=True):
     Return a 5-tuple: (scheme, netloc, path, query, fragment).
     Note that we don't break the components up in smaller bits
     (e.g. netloc is a single string) and we don't expand % escapes."""
+
     allow_fragments = bool(allow_fragments)
     key = url, scheme, allow_fragments, type(url), type(scheme)
     cached = _parse_cache.get(key, None)
@@ -204,6 +212,12 @@ def urlsplit(url, scheme='', allow_fragments=True):
         return cached
     if len(_parse_cache) >= MAX_CACHE_SIZE: # avoid runaway growth
         clear_cache()
+
+    # Only lstrip url as some applications rely on preserving trailing space.
+    # (https://url.spec.whatwg.org/#concept-basic-url-parser would strip both)
+    url = url.lstrip(_WHATWG_C0_CONTROL_OR_SPACE)
+    scheme = scheme.strip(_WHATWG_C0_CONTROL_OR_SPACE)
+
     netloc = query = fragment = ''
     i = url.find(':')
     if i > 0:
diff --git a/Misc/NEWS.d/next/Security/2023-03-07-20-59-17.gh-issue-102153.14CLSZ.rst b/Misc/NEWS.d/next/Security/2023-03-07-20-59-17.gh-issue-102153.14CLSZ.rst
new file mode 100644
index 00000000000000..e57ac4ed3ac5d7
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2023-03-07-20-59-17.gh-issue-102153.14CLSZ.rst
@@ -0,0 +1,3 @@
+:func:`urllib.parse.urlsplit` now strips leading C0 control and space
+characters following the specification for URLs defined by WHATWG in
+response to CVE-2023-24329. Patch by Illia Volochii.