diff -rud -u cpython/Lib.old/test/test_wsgiref.py cpython/Lib/test/test_wsgiref.py
--- cpython/Lib.old/test/test_wsgiref.py	2014-10-17 01:53:14.000000000 +0200
+++ cpython/Lib/test/test_wsgiref.py	2014-12-10 13:38:04.000000000 +0100
@@ -46,6 +46,14 @@
     ])
     return ["Hello, world!"]
 
+def hello_ml_app(environ,start_response):
+    start_response("200 OK", [
+        ('Content-Type','text/plain'),
+        ('X-Multiline','first\r\n second\r\n third'),
+        ('Date','Mon, 05 Jun 2006 18:49:54 GMT')
+    ])
+    return ["Hello, world!"]
+
 def run_amock(app=hello_app, data="GET / HTTP/1.0\n\n"):
     server = make_server("", 80, app, MockServer, MockHandler)
     inp, out, err, olderr = StringIO(data), StringIO(), StringIO(), sys.stderr
@@ -98,11 +106,13 @@
 
 class IntegrationTests(TestCase):
 
-    def check_hello(self, out, has_length=True):
+    def check_hello(self, out, has_length=True, multiline=False):
+        multiline = "X-Multiline: first\r\n second\r\n third\r\n" if multiline else ''
         self.assertEqual(out,
             "HTTP/1.0 200 OK\r\n"
             "Server: WSGIServer/0.1 Python/"+sys.version.split()[0]+"\r\n"
             "Content-Type: text/plain\r\n"
+            +multiline+
             "Date: Mon, 05 Jun 2006 18:49:54 GMT\r\n" +
             (has_length and  "Content-Length: 13\r\n" or "") +
             "\r\n"
@@ -113,6 +123,10 @@
         out, err = run_amock()
         self.check_hello(out)
 
+    def test_ml_hello(self):
+        out, err = run_amock(app=hello_ml_app)
+        self.check_hello(out, multiline=True)
+
     def test_request_length(self):
         out, err = run_amock(data="GET " + ("x" * 65537) + " HTTP/1.0\n\n")
         self.assertEqual(out.splitlines()[0],
@@ -123,6 +137,12 @@
         # the middleware doesn't support len(), so content-length isn't there
         self.check_hello(out, has_length=False)
 
+    def test_validate_hello_ml(self):
+        out, err = run_amock(validator(hello_ml_app))
+        self.assertTrue(out.endswith(
+            "A server error occurred.  Please contact the administrator."
+        ))
+
     def test_simple_validation_error(self):
         def bad_app(environ,start_response):
             start_response("200 OK", ('Content-Type','text/plain'))
diff -rud -u cpython/Lib.old/wsgiref/simple_server.py cpython/Lib/wsgiref/simple_server.py
--- cpython/Lib.old/wsgiref/simple_server.py	2014-10-17 01:53:18.000000000 +0200
+++ cpython/Lib/wsgiref/simple_server.py	2014-12-10 13:37:56.000000000 +0100
@@ -96,8 +96,7 @@
         if length:
             env['CONTENT_LENGTH'] = length
 
-        for h in self.headers.headers:
-            k,v = h.split(':',1)
+        for k,v in self.headers.dict.items():
             k=k.replace('-','_').upper(); v=v.strip()
             if k in env:
                 continue                    # skip content length, type,etc.