diff --git a/Misc/NEWS b/Misc/NEWS
index c55dc4a2e01..d3489d1ecf9 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@ What's New in Python 3.3.7?
 Core and Builtins
 -----------------
 
+- Issue #28648: Fixed crash in Py_DecodeLocale() in debug build on Mac OS X
+  when decode astral characters.  Patch by Xiang Zhang.
+
 - Issue #26171: Fix possible integer overflow and heap corruption in
   zipimporter.get_data().
 
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index cf4f8421eb6..24eda6be9bf 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -4896,7 +4896,7 @@ _Py_DecodeUTF8_surrogateescape(const char *s, Py_ssize_t size)
 #if SIZEOF_WCHAR_T == 4
             assert(0);
 #else
-            assert(Py_UNICODE_IS_SURROGATE(ch));
+            assert(ch > 0xFFFF && ch <= MAX_UNICODE);
             /*  compute and append the two surrogates: */
             unicode[outpos++] = (wchar_t)Py_UNICODE_HIGH_SURROGATE(ch);
             unicode[outpos++] = (wchar_t)Py_UNICODE_LOW_SURROGATE(ch);