Vulnerability-Lookup

rustsec-2026-0256

Vulnerability from osv_rustsec

Published

2026-08-11 12:00

Modified

2026-08-12 10:22

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.

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.

References

URL

Type

	https://crates.io/crates/circular-buffer	PACKAGE
	https://rustsec.org/advisories/RUSTSEC-2026-0256.html	ADVISORY
	https://github.com/andreacorbellini/rust-circular…	WEB

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "memory-corruption"
        ],
        "cvss": null,
        "informational": "unsound"
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [
            "circular_buffer::CircularBuffer::clear",
            "circular_buffer::CircularBuffer::extend_from_slice",
            "circular_buffer::CircularBuffer::truncate_back",
            "circular_buffer::CircularBuffer::truncate_front"
          ],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "circular-buffer",
        "purl": "pkg:cargo/circular-buffer"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.0.0-0"
            },
            {
              "fixed": "2.0.1"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "Several methods in `circular-buffer` drop elements before updating the buffer\u0027s start/end metadata. If an element\u0027s `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 \u2014 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\u0027s start/end metadata before the elements are dropped.",
  "id": "RUSTSEC-2026-0256",
  "modified": "2026-08-12T10:22:26Z",
  "published": "2026-08-11T12:00:00Z",
  "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"
    }
  ],
  "related": [],
  "severity": [],
  "summary": "Panic-safety unsoundness in `truncate_back`, `truncate_front`, `clear`, and `extend_from_slice` (use-after-free / double-free)"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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