diff -r bff31254a0f0 Lib/test/test_raise.py
--- a/Lib/test/test_raise.py	Sat Jul 16 16:13:51 2016 -0700
+++ b/Lib/test/test_raise.py	Mon Jul 18 21:29:53 2016 +0800
@@ -3,6 +3,7 @@
 
 """Tests for the raise statement."""
 
+from multiprocessing.pool import ThreadPool
 from test import support
 import re
 import sys
@@ -147,6 +148,14 @@
         except AssertionError as e:
             self.assertEqual(str(e), "(3,)")
 
+    @support.reap_threads
+    def test_reraise_in_new_thread(self):
+        # issue #27558
+        def reraise():
+            raise
+        pool = ThreadPool(processes=1)
+        self.assertRaises(RuntimeError, pool.apply_async(reraise).get)
+        pool.close()
 
 
 class TestCause(unittest.TestCase):
diff -r bff31254a0f0 Python/ceval.c
--- a/Python/ceval.c	Sat Jul 16 16:13:51 2016 -0700
+++ b/Python/ceval.c	Mon Jul 18 21:29:53 2016 +0800
@@ -4141,7 +4141,7 @@
         type = tstate->exc_type;
         value = tstate->exc_value;
         tb = tstate->exc_traceback;
-        if (type == Py_None) {
+        if (type == Py_None || type == NULL) {
             PyErr_SetString(PyExc_RuntimeError,
                             "No active exception to reraise");
             return 0;