From 0742abdc48886b74ed3b66985a54bb1c32802670 Mon Sep 17 00:00:00 2001
From: TAGAMI Yukihiro <tagami.yukihiro@gmail.com>
Date: Sat, 2 Oct 2021 18:57:13 +0900
Subject: [PATCH] bpo-45329: Fix freed memory access in pyexpat.c (GH-28649)

---
 .../next/Library/2021-10-01-13-09-53.bpo-45329.9iMYaO.rst       | 2 ++
 Modules/pyexpat.c                                               | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2021-10-01-13-09-53.bpo-45329.9iMYaO.rst

diff --git a/Misc/NEWS.d/next/Library/2021-10-01-13-09-53.bpo-45329.9iMYaO.rst b/Misc/NEWS.d/next/Library/2021-10-01-13-09-53.bpo-45329.9iMYaO.rst
new file mode 100644
index 00000000000..b4bedbc278e
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-10-01-13-09-53.bpo-45329.9iMYaO.rst
@@ -0,0 +1,2 @@
+Fix freed memory access in :class:`pyexpat.xmlparser` when building it with an
+installed expat library <= 2.2.0.
diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c
index ec684638ead..b3d9bdda7e7 100644
--- a/Modules/pyexpat.c
+++ b/Modules/pyexpat.c
@@ -1204,10 +1204,10 @@ static void
 xmlparse_dealloc(xmlparseobject *self)
 {
     PyObject_GC_UnTrack(self);
+    (void)xmlparse_clear(self);
     if (self->itself != NULL)
         XML_ParserFree(self->itself);
     self->itself = NULL;
-    (void)xmlparse_clear(self);
 
     if (self->handlers != NULL) {
         PyMem_Free(self->handlers);