Double-free in `vmem` storage reachable from safe Rust (predecessor of `oneringbuf`)

mutringbuf is the archived predecessor of oneringbuf — the crate was renamed and the GitHub repository was archived on 2025-11-20. All released versions up to 1.0.0 carry the same vmem-feature double-free bug that affects oneringbuf, with the same code paths and the same reproduction shape. When...