gh-142783: Fix possible use after free in zoneinfo module

Lib/test/test_zoneinfo/test_zoneinfo.py

@@ -1559,22 +1559,9 @@ def test_weak_cache_descriptor_use_after_free(self):
         if "UTC" not in available_zones:
             raise unittest.SkipTest("No time zone data available")
 
-        class Cache:
-            def __init__(self):
-                self.data = {}
-
-            def get(self, key, default=None):
-                return self.data.get(key, default)
-
-            def setdefault(self, key, default):
-                return self.data.setdefault(key, default)
-
-            def clear(self, *args, **kwargs):
-                self.data.clear()
-
         class BombDescriptor:
             def __get__(self, obj, owner):
-                return Cache()
+                return dict()
 
         class EvilZoneInfo(ZoneInfo):
             pass

Misc/NEWS.d/next/Library/2025-12-16-14-49-19.gh-issue-142783.VPV1ig.rst

@@ -1,3 +1 @@
-Fix zoneinfo use-after-free with descriptor _weak_cache. Return new
-reference from get_weak_cache() instead of borrowed reference to prevent
-premature object free.
+Fix zoneinfo use-after-free with descriptor _weak_cache. a descriptor as _weak_cache could cause crashes during object creation. The fix ensures proper reference counting for descriptor-provided objects.