OwnedAlloc::drop in place destroys the contained value by hand, then commits the ownership transfer with mem::forget(self) — which lives inside into raw and so runs only after the destruction. T::drop is user code and may panic. If it does, the forget is skipped and the still-live OwnedAlloc unwinds, whose destructor drops the same T a second time and then deallocates. For a T that owns an allocation, the same block is freed twice — a double free (CWE-415). That destructor also reads the already-destroyed value through Layout::for value before deallocating, a use-after-free (CWE-416).

MaybeUninitAlloc::drop in place delegates to the same function, so both public entry points are affected. Storing a value whose Drop can panic and calling either is enough — no unsafe on the caller's side.

No fixed release is available. The crate has had no release since 2018 and the maintainer has not responded to the report, nor to the one on lockfree, which is published from the same account. forget inner leaks the value instead of destroying it, which is safe.