diff --git a/Lib/test/test_curses.py b/Lib/test/test_curses.py
index 31b7371abd3230..82bb10ad58c635 100644
--- a/Lib/test/test_curses.py
+++ b/Lib/test/test_curses.py
@@ -514,6 +514,12 @@ def test_in_wstr(self):
                     self.assertEqual(stdscr.in_wstr(0, 0, len(s)), s)
                     self.assertIsInstance(stdscr.instr(0, 0, len(s)), bytes)
 
+        # Reading no characters gives an empty string, like instr() and
+        # in_wchstr() do.  curses does not terminate the buffer in this case.
+        stdscr.addstr(0, 0, 'abz')
+        self.assertEqual(stdscr.in_wstr(0, 0, 0), '')
+        self.assertEqual(stdscr.in_wstr(0), '')
+
     def test_complexchar(self):
         # A complexchar is a styled wide-character cell: str() is its text,
         # and the attr and pair attributes are its rendition.
diff --git a/Modules/_cursesmodule.c b/Modules/_cursesmodule.c
index 2b580c3475e6d9..7d794b879e34ff 100644
--- a/Modules/_cursesmodule.c
+++ b/Modules/_cursesmodule.c
@@ -3850,7 +3850,7 @@ PyCursesWindow_in_wstr(PyObject *op, PyObject *args)
     }
 
     n = Py_MIN(n, max_buf_size - 1);
-    wchar_t *buf = PyMem_New(wchar_t, n + 1);
+    wchar_t *buf = PyMem_Calloc(n + 1, sizeof(wchar_t));
     if (buf == NULL) {
         return PyErr_NoMemory();
     }