{"id":"RUSTSEC-2026-0256","summary":"Panic-safety unsoundness in `truncate_back`, `truncate_front`, `clear`, and `extend_from_slice` (use-after-free / double-free)","details":"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.\n\n## Impact\n\n- **CWE-415 (Double Free):** the same allocation is freed twice.\n- **CWE-416 (Use-After-Free):** a freed allocation is accessed during a repeated `Drop`.\n\nReachable entirely from safe Rust via `catch_unwind` with element types whose `Drop` can panic.\n\n## Fix\n\nFixed in `circular-buffer` 2.0.1 by adjusting the buffer's start/end metadata before the elements are dropped.","modified":"2026-08-12T10:30:18.189895730Z","published":"2026-08-11T12:00:00Z","database_specific":{"license":"CC0-1.0"},"references":[{"type":"PACKAGE","url":"https://crates.io/crates/circular-buffer"},{"type":"ADVISORY","url":"https://rustsec.org/advisories/RUSTSEC-2026-0256.html"},{"type":"WEB","url":"https://github.com/andreacorbellini/rust-circular-buffer/blob/master/CHANGELOG.md"}],"affected":[{"package":{"name":"circular-buffer","ecosystem":"crates.io","purl":"pkg:cargo/circular-buffer"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"2.0.1"}]}],"ecosystem_specific":{"affected_functions":null,"affects":{"functions":["circular_buffer::CircularBuffer::clear","circular_buffer::CircularBuffer::extend_from_slice","circular_buffer::CircularBuffer::truncate_back","circular_buffer::CircularBuffer::truncate_front"],"arch":[],"os":[]}},"database_specific":{"cvss":null,"informational":"unsound","source":"https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0256.json","categories":["memory-corruption"]}}],"schema_version":"1.9.0"}