diff --git a/Misc/NEWS b/Misc/NEWS
index 7eac644..aa9020e 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -29,6 +29,11 @@
 
 - Issue #10464: netrc now correctly handles lines with embedded '#' characters.
 
+Extensions
+----------
+
+- Issue #678250: Make mmap flush a noop on ACCESS_READ and ACCESS_COPY.
+
 Tests
 -----