Expat could crash if given the wrong kind of input by never stopping its
tokenizing step.
Thanks to Ivan Krstić for the patch.
diff --git a/Misc/NEWS b/Misc/NEWS
index 54758ae..42e14a2 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -1227,6 +1227,9 @@
Extension Modules
-----------------
+- Fix a segfault in expat when given a specially crafted input lead to the
+ tokenizer not stopping.
+
- Issue #6561: '\d' in a regex now matches only characters with
Unicode category 'Nd' (Number, Decimal Digit). Previously it also
matched characters with category 'No'.