RUSTSEC-2026-0204: Invalid pointer dereference in `fmt::Pointer` impl for `Atomic` and `Shared` when the underlying pointer is invalid

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Details
Package	crossbeam-epoch
Version	0.9.18
URL	crossbeam-rs/crossbeam#1276
Patched Versions	>=0.9.20
Unaffected Versions	<0.9.0

Affected versions of fmt::Display dereference the underlying pointer. This causes a invalid pointer dereference e.g., when a pointer created with Atomic::null or Shared::null. fmt::Debug impls and pre-0.9 fmt::Display impls, which do not dereference pointers, are not affected by this issue.