diff -r bc88690df059 Lib/multiprocessing/connection.py
--- a/Lib/multiprocessing/connection.py	Tue Jan 29 13:35:00 2013 +0100
+++ b/Lib/multiprocessing/connection.py	Tue Jan 29 14:00:58 2013 +0100
@@ -496,13 +496,13 @@ if sys.platform != 'win32':
         Returns pair of connection objects at either end of a pipe
         '''
         if duplex:
-            s1, s2 = socket.socketpair()
+            s1, s2 = socket.socketpair(cloexec=True)
             s1.setblocking(True)
             s2.setblocking(True)
             c1 = Connection(s1.detach())
             c2 = Connection(s2.detach())
         else:
-            fd1, fd2 = os.pipe()
+            fd1, fd2 = os.pipe(cloexec=True)
             c1 = Connection(fd1, writable=False)
             c2 = Connection(fd2, readable=False)
 
@@ -559,7 +559,7 @@ class SocketListener(object):
     Representation of a socket which is bound to an address and listening
     '''
     def __init__(self, address, family, backlog=1):
-        self._socket = socket.socket(getattr(socket, family))
+        self._socket = socket.socket(getattr(socket, family), cloexec=True)
         try:
             # SO_REUSEADDR has different semantics on Windows (issue #2550).
             if os.name == 'posix':
@@ -598,7 +598,7 @@ def SocketClient(address):
     Return a connection object connected to the socket given by `address`
     '''
     family = address_type(address)
-    with socket.socket( getattr(socket, family) ) as s:
+    with socket.socket( getattr(socket, family) , cloexec=True) as s:
         s.setblocking(True)
         s.connect(address)
         return Connection(s.detach())
diff -r bc88690df059 Lib/multiprocessing/forking.py
--- a/Lib/multiprocessing/forking.py	Tue Jan 29 13:35:00 2013 +0100
+++ b/Lib/multiprocessing/forking.py	Tue Jan 29 14:00:58 2013 +0100
@@ -90,7 +90,7 @@ if sys.platform != 'win32':
             sys.stderr.flush()
             self.returncode = None
 
-            r, w = os.pipe()
+            r, w = os.pipe(cloexec=True)
             self.sentinel = r
 
             self.pid = os.fork()
@@ -211,7 +211,7 @@ else:
             prep_data = get_preparation_data(process_obj._name)
 
             # create pipe for communication with child
-            rfd, wfd = os.pipe()
+            rfd, wfd = os.pipe(cloexec=True)
 
             # get handle for read end of the pipe and make it inheritable
             rhandle = duplicate(msvcrt.get_osfhandle(rfd), inheritable=True)
diff -r bc88690df059 Lib/multiprocessing/process.py
--- a/Lib/multiprocessing/process.py	Tue Jan 29 13:35:00 2013 +0100
+++ b/Lib/multiprocessing/process.py	Tue Jan 29 14:00:58 2013 +0100
@@ -241,7 +241,7 @@ class Process(object):
             if sys.stdin is not None:
                 try:
                     sys.stdin.close()
-                    sys.stdin = open(os.devnull)
+                    sys.stdin = open(os.devnull, cloexec=True)
                 except (OSError, ValueError):
                     pass
             old_process = _current_process
diff -r bc88690df059 Lib/subprocess.py
--- a/Lib/subprocess.py	Tue Jan 29 13:35:00 2013 +0100
+++ b/Lib/subprocess.py	Tue Jan 29 14:00:58 2013 +0100
@@ -793,15 +793,15 @@ class Popen(object):
                 errread = msvcrt.open_osfhandle(errread.Detach(), 0)
 
         if p2cwrite != -1:
-            self.stdin = io.open(p2cwrite, 'wb', bufsize)
+            self.stdin = io.open(p2cwrite, 'wb', bufsize, cloexec=True)
             if universal_newlines:
                 self.stdin = io.TextIOWrapper(self.stdin, write_through=True)
         if c2pread != -1:
-            self.stdout = io.open(c2pread, 'rb', bufsize)
+            self.stdout = io.open(c2pread, 'rb', bufsize, cloexec=True)
             if universal_newlines:
                 self.stdout = io.TextIOWrapper(self.stdout)
         if errread != -1:
-            self.stderr = io.open(errread, 'rb', bufsize)
+            self.stderr = io.open(errread, 'rb', bufsize, cloexec=True)
             if universal_newlines:
                 self.stderr = io.TextIOWrapper(self.stderr)
 
@@ -870,7 +870,7 @@ class Popen(object):
 
     def _get_devnull(self):
         if not hasattr(self, '_devnull'):
-            self._devnull = os.open(os.devnull, os.O_RDWR)
+            self._devnull = os.open(os.devnull, os.O_RDWR, cloexec=True)
         return self._devnull
 
     def communicate(self, input=None, timeout=None):