{"id":"RUSTSEC-2026-0256","aliases":[],"status":"published","title":"Panic-safety unsoundness in `truncate_back`, `truncate_front`, `clear`, and `extend_from_slice` (use-after-free / double-free)","description":"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.","facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"published":"2026-08-11T12:00:00Z","modified":"2026-08-12T10:30:20Z","fixes":[{"ecosystem":"crates.io","package":"circular-buffer","fixed_in":["2.0.1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"crates.io","package":"circular-buffer","ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"2.0.1"}]}]}],"references":[{"url":"https://crates.io/crates/circular-buffer","tags":["package"]},{"url":"https://rustsec.org/advisories/RUSTSEC-2026-0256.html","tags":["advisory"]},{"url":"https://github.com/andreacorbellini/rust-circular-buffer/blob/master/CHANGELOG.md","tags":["web"]}],"sources":{"osv":[{"id":"RUSTSEC-2026-0256","title":"Panic-safety unsoundness in `truncate_back`, `truncate_front`, `clear`, and `extend_from_slice` (use-after-free / double-free)","description":"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.","status":"published","published":"2026-08-11T12:00:00Z","modified":"2026-08-12T10:30:20.590320658Z","updated_at":"2026-11-02T15:53:40.430679Z"}]}}