Several methods in circular-buffer drop elements before updating the buffer's start/end metadata. If an element's Drop panics during the drop, the metadata update is skipped, so the buffer still treats the already-dropped elements as live. When the buffer is later dropped (or used after the panic is caught), those elements are visited again — a use-after-free / double-free reachable from safe Rust.

Reachable entirely from safe Rust via catch unwind with element types whose Drop can panic.

Fixed in circular-buffer 2.0.1 by adjusting the buffer's start/end metadata before the elements are dropped.