1 files changed, 3 insertions, 0 deletions
diff --git a/Misc/NEWS b/Misc/NEWS
index b7e73e9..907e140 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -27,6 +27,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #11259: asynchat.async_chat().set_terminator() now raises a ValueError
+  if the number of received bytes is negative.
+
 - Issue #12523: asynchat.async_chat.push() now raises a TypeError if it doesn't
   get a bytes string