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/ACKS b/Misc/ACKS
index defa802..dc87dc2 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -183,6 +183,7 @@
 Dima Dorfman
 Cesar Douady
 Dean Draayer
+Fred L. Drake, Jr.
 John DuBois
 Paul Dubois
 Graham Dumpleton
@@ -371,7 +372,6 @@
 Lucas de Jonge
 John Jorgensen
 Jens B. Jorgensen
-Fred L. Drake, Jr.
 Andreas Jung
 Tattoo Mabonzo K.
 Bob Kahn
@@ -408,6 +408,7 @@
 Michael Kremer
 Fabian Kreutz
 Hannu Krosing
+Ivan Krstić
 Andrew Kuchling
 Vladimir Kushnir
 Cameron Laird
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'.