diff -r 1aa6751b298f Lib/email/feedparser.py
--- a/Lib/email/feedparser.py	Mon Dec 16 09:05:44 2013 -0600
+++ b/Lib/email/feedparser.py	Mon Dec 16 20:12:15 2013 +0000
@@ -33,7 +33,7 @@
 NLCRE_crack = re.compile('(\r\n|\r|\n)')
 # RFC 2822 $3.6.8 Optional fields.  ftext is %d33-57 / %d59-126, Any character
 # except controls, SP, and ":".
-headerRE = re.compile(r'^(From |[\041-\071\073-\176]{1,}:|[\t ])')
+headerRE = re.compile(r'^(From |[\041-\071\073-\176]*:|[\t ])')
 EMPTYSTRING = ''
 NL = '\n'
 
@@ -492,6 +492,15 @@
             # There will always be a colon, because if there wasn't the part of
             # the parser that calls us would have started parsing the body.
             i = line.find(':')
+
+            # If the colon is on the start of the line the header is clearly
+            # malformed, but we might be able to salvage the rest of the
+            # message. Track the error but keep going.
+            if i == 0:
+                defect = errors.InvalidHeaderDefect("Missing header name.")
+                self._cur.defects.append(defect)
+                continue
+
             assert i>0, "_parse_headers fed line with no : and no leading WS"
             lastheader = line[:i]
             lastvalue = [line]
diff -r 1aa6751b298f Lib/test/test_email/test_email.py
--- a/Lib/test/test_email/test_email.py	Mon Dec 16 09:05:44 2013 -0600
+++ b/Lib/test/test_email/test_email.py	Mon Dec 16 20:12:15 2013 +0000
@@ -729,6 +729,13 @@
             w4kgdGVzdGFiYwo=
             """))
 
+    def test_empty_header_name_handled(self):
+        # Issue 19996
+        msg = email.message_from_string("First: val\n: bad\nSecond: val")
+        self.assertEqual(msg['First'], 'val')
+        self.assertEqual(msg['Second'], 'val')
+
+
 
 # Test the email.encoders module
 class TestEncoders(unittest.TestCase):
diff -r 1aa6751b298f Lib/test/test_httplib.py
--- a/Lib/test/test_httplib.py	Mon Dec 16 09:05:44 2013 -0600
+++ b/Lib/test/test_httplib.py	Mon Dec 16 20:12:15 2013 +0000
@@ -155,6 +155,18 @@
         conn.request('GET', '/foo')
         self.assertTrue(sock.data.startswith(expected))
 
+    def test_malformed_headers_coped_with(self):
+        # Issue 19996
+        body = "HTTP/1.1 200 OK\r\nFirst: val\r\n: nval\r\nSecond: val\r\n\r\n"
+        sock = FakeSocket(body)
+        resp = client.HTTPResponse(sock)
+        resp.begin()
+
+        self.assertEqual(resp.getheader('First'), 'val')
+        self.assertEqual(resp.getheader('Second'), 'val')
+
+
+
 
 class BasicTest(TestCase):
     def test_status_lines(self):