python
diff --git a/‎Lib/test/test_deque.py
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+5-1Lines changed: 5 additions & 1 deletion b/‎Lib/test/test_deque.py
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+5-1Lines changed: 5 additions & 1 deletion
diff --git a/‎Misc/NEWS.d/next/Security/2024-02-12-00-33-01.gh-issue-115243.e1oGX8.rst
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+1Lines changed: 1 addition & 0 deletions b/‎Misc/NEWS.d/next/Security/2024-02-12-00-33-01.gh-issue-115243.e1oGX8.rst
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+1Lines changed: 1 addition & 0 deletions
diff --git a/‎Modules/_collectionsmodule.c
Copy file name to clipboardExpand all lines: Modules/_collectionsmodule.c
+2-1Lines changed: 2 additions & 1 deletion b/‎Modules/_collectionsmodule.c
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+2-1Lines changed: 2 additions & 1 deletion
@@ -166,7 +166,7 @@ def test_contains(self):
         with self.assertRaises(RuntimeError):
             n in d
 
-    def test_contains_count_stop_crashes(self):
+    def test_contains_count_index_stop_crashes(self):
         class A:
             def __eq__(self, other):
                 d.clear()
@@ -178,6 +178,10 @@ def __eq__(self, other):
         with self.assertRaises(RuntimeError):
             _ = d.count(3)
 
+        d = deque([A()])
+        with self.assertRaises(RuntimeError):
+            d.index(0)
+
     def test_extend(self):
         d = deque('a')
         self.assertRaises(TypeError, d.extend, 1)
 
@@ -0,0 +1 @@
+Fix possible crashes in :meth:`collections.deque.index` when the deque is concurrently modified.
@@ -1084,8 +1084,9 @@ deque_index(dequeobject *deque, PyObject *const *args, Py_ssize_t nargs)
     n = stop - i;
     while (--n >= 0) {
         CHECK_NOT_END(b);
-        item = b->data[index];
+        item = Py_NewRef(b->data[index]);
         cmp = PyObject_RichCompareBool(item, v, Py_EQ);
+        Py_DECREF(item);
         if (cmp > 0)
             return PyLong_FromSsize_t(stop - n - 1);
         if (cmp < 0)
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+Fix possible crashes in :meth:`collections.deque.index` when the deque is concurrently modified.