Added NEWS entry

Author: CharlieKerfoot

Misc/NEWS.d/next/Core_and_Builtins/2026-04-25-19-46-23.gh-issue-149000.jvDIwy.rst

@@ -0,0 +1,8 @@
+"- Issue #<n>: " or "- gh-issue-<n>: " or that sort of stuff.
+###########################################################################
+
+Fix a race in the per-interpreter ``pickle.dumps``/``pickle.loads`` cache
+used by cross-interpreter data transfer. Concurrent use (first time) from
+multiple threads in the same interpreter could leak a reference to the
+imported attribute and also potentially expose a torn pointer read. The
+cache is now populated with an atomic compare-exchange.