Reported

August 11, 2026

Issued

August 12, 2026

Package

circular-buffer (crates.io)

Type

INFO Unsound

Categories

• memory-corruption

Keywords

#panic-safety #memory-safety #use-after-free #double-free

References

• https://github.com/andreacorbellini/rust-circular-buffer/blob/master/CHANGELOG.md

Patched

• >=2.0.1

Affected Functions

Version

circular_buffer::CircularBuffer::clear

• <2.0.1

circular_buffer::CircularBuffer::extend_from_slice

• <2.0.1

circular_buffer::CircularBuffer::truncate_back

• <2.0.1

circular_buffer::CircularBuffer::truncate_front

• <2.0.1

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.

Impact

• CWE-415 (Double Free): the same allocation is freed twice.
• CWE-416 (Use-After-Free): a freed allocation is accessed during a repeated Drop.

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

Fix

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

Advisory available under CC0-1.0 license.