diff --git a/Lib/urllib/parse.py b/Lib/urllib/parse.py
index e2b6f133e..f0d9d4d80 100644
--- a/Lib/urllib/parse.py
+++ b/Lib/urllib/parse.py
@@ -77,6 +77,9 @@ scheme_chars = ('abcdefghijklmnopqrstuvwxyz'
                 '0123456789'
                 '+-.')
 
+# Unsafe bytes to be removed per WHATWG spec
+_UNSAFE_URL_BYTES_TO_REMOVE = ['\t', '\r', '\n']
+
 # XXX: Consider replacing with functools.lru_cache
 MAX_CACHE_SIZE = 20
 _parse_cache = {}
@@ -414,6 +417,11 @@ def _checknetloc(netloc):
             raise ValueError("netloc '" + netloc + "' contains invalid " +
                              "characters under NFKC normalization")
 
+def _remove_unsafe_bytes_from_url(url):
+    for b in _UNSAFE_URL_BYTES_TO_REMOVE:
+        url = url.replace(b, "")
+    return url
+
 def urlsplit(url, scheme='', allow_fragments=True):
     """Parse a URL into 5 components:
     <scheme>://<netloc>/<path>?<query>#<fragment>
@@ -421,6 +429,8 @@ def urlsplit(url, scheme='', allow_fragments=True):
     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."""
     url, scheme, _coerce_result = _coerce_args(url, scheme)
+    url = _remove_unsafe_bytes_from_url(url)
+    scheme = _remove_unsafe_bytes_from_url(scheme)
     allow_fragments = bool(allow_fragments)
     key = url, scheme, allow_fragments, type(url), type(scheme)
     cached = _parse_cache.get(key, None)
@@ -631,6 +641,8 @@ def unquote(string, encoding='utf-8', errors='replace'):
 
     unquote('abc%20def') -> 'abc def'.
     """
+    if isinstance(string, bytes):
+        raise TypeError('Expected str, got bytes')
     if '%' not in string:
         string.split
         return string
@@ -648,7 +660,7 @@ def unquote(string, encoding='utf-8', errors='replace'):
 
 
 def parse_qs(qs, keep_blank_values=False, strict_parsing=False,
-             encoding='utf-8', errors='replace', max_num_fields=None):
+             encoding='utf-8', errors='replace', max_num_fields=None, separator='&'):
     """Parse a query given as a string argument.
 
         Arguments:
@@ -672,12 +684,15 @@ def parse_qs(qs, keep_blank_values=False, strict_parsing=False,
         max_num_fields: int. If set, then throws a ValueError if there
             are more than n fields read by parse_qsl().
 
+        separator: str. The symbol to use for separating the query arguments.
+            Defaults to &.
+
         Returns a dictionary.
     """
     parsed_result = {}
     pairs = parse_qsl(qs, keep_blank_values, strict_parsing,
                       encoding=encoding, errors=errors,
-                      max_num_fields=max_num_fields)
+                      max_num_fields=max_num_fields, separator=separator)
     for name, value in pairs:
         if name in parsed_result:
             parsed_result[name].append(value)
@@ -687,7 +702,7 @@ def parse_qs(qs, keep_blank_values=False, strict_parsing=False,
 
 
 def parse_qsl(qs, keep_blank_values=False, strict_parsing=False,
-              encoding='utf-8', errors='replace', max_num_fields=None):
+              encoding='utf-8', errors='replace', max_num_fields=None, separator='&'):
     """Parse a query given as a string argument.
 
         Arguments:
@@ -710,19 +725,26 @@ def parse_qsl(qs, keep_blank_values=False, strict_parsing=False,
         max_num_fields: int. If set, then throws a ValueError
             if there are more than n fields read by parse_qsl().
 
+        separator: str. The symbol to use for separating the query arguments.
+            Defaults to &.
+
         Returns a list, as G-d intended.
     """
     qs, _coerce_result = _coerce_args(qs)
+    separator, _ = _coerce_args(separator)
+
+    if not separator or (not isinstance(separator, (str, bytes))):
+        raise ValueError("Separator must be of type string or bytes.")
 
     # If max_num_fields is defined then check that the number of fields
     # is less than max_num_fields. This prevents a memory exhaustion DOS
     # attack via post bodies with many fields.
     if max_num_fields is not None:
-        num_fields = 1 + qs.count('&') + qs.count(';')
+        num_fields = 1 + qs.count(separator)
         if max_num_fields < num_fields:
             raise ValueError('Max number of fields exceeded')
 
-    pairs = [s2 for s1 in qs.split('&') for s2 in s1.split(';')]
+    pairs = [s1 for s1 in qs.split(separator)]
     r = []
     for name_value in pairs:
         if not name_value and not strict_parsing:
diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py
index e44073886..5f67077fb 100644
--- a/Lib/urllib/request.py
+++ b/Lib/urllib/request.py
@@ -779,7 +779,11 @@ def _parse_proxy(proxy):
             raise ValueError("proxy URL with no authority: %r" % proxy)
         # We have an authority, so for RFC 3986-compliant URLs (by ss 3.
         # and 3.3.), path is empty or starts with '/'
-        end = r_scheme.find("/", 2)
+        if '@' in r_scheme:
+            host_separator = r_scheme.find('@')
+            end = r_scheme.find("/", host_separator)
+        else:
+            end = r_scheme.find("/", 2)
         if end == -1:
             end = None
         authority = r_scheme[2:end]
@@ -947,7 +951,7 @@ class AbstractBasicAuthHandler:
     # (single quotes are a violation of the RFC, but appear in the wild)
     rx = re.compile('(?:^|,)'   # start of the string or ','
                     '[ \t]*'    # optional whitespaces
-                    '([^ \t]+)' # scheme like "Basic"
+                    '([^ \t,]+)' # scheme like "Basic"
                     '[ \t]+'    # mandatory whitespaces
                     # realm=xxx
                     # realm='xxx'
@@ -2604,6 +2608,11 @@ def _proxy_bypass_macosx_sysconf(host, proxy_settings):
                 mask = 8 * (m.group(1).count('.') + 1)
             else:
                 mask = int(mask[1:])
+
+            if mask < 0 or mask > 32:
+                # System libraries ignore invalid prefix lengths
+                continue
+
             mask = 32 - mask
 
             if (hostIP >> mask) == (base >> mask):