update NEWS
diff --git a/Misc/NEWS b/Misc/NEWS
index 465c9d0..6618a15 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,8 @@
 Core and Builtins
 -----------------
 
+- Issue #5666: Py_BuildValue's 'c' code should create byte strings.
+
 - Issue #5499: The 'c' code for argument parsing functions now only accepts a
   byte, and the 'C' code only accepts a unicode character.