rustsec-2024-0378
Vulnerability from osv_rustsec
Published
2024-10-12 12:00
Modified
2025-10-28 06:02
Summary
Risk of use-after-free in `borrowed` reads from Python weak references
Details

The family of functions to read "borrowed" values from Python weak references were fundamentally unsound, because the weak reference does itself not have ownership of the value. At any point the last strong reference could be cleared and the borrowed value would become dangling.

In PyO3 0.22.4 these functions have all been deprecated and patched to leak a strong reference as a mitigation. PyO3 0.23 will remove these functions entirely.

To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "memory-corruption"
        ],
        "cvss": null,
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [
            "pyo3::types::PyWeakrefMethods::get_object_borrowed",
            "pyo3::types::PyWeakrefMethods::upgrade_borrowed",
            "pyo3::types::PyWeakrefMethods::upgrade_borrowed_as",
            "pyo3::types::PyWeakrefMethods::upgrade_borrowed_as_exact",
            "pyo3::types::PyWeakrefMethods::upgrade_borrowed_as_unchecked"
          ],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "pyo3",
        "purl": "pkg:cargo/pyo3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.22.0"
            },
            {
              "fixed": "0.22.4"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "CVE-2024-9979",
    "GHSA-6jgw-rgmm-7cv6"
  ],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "The family of functions to read \"borrowed\" values from Python weak references\nwere fundamentally unsound, because the weak reference does itself not have\nownership of the value. At any point the last strong reference could\nbe cleared and the borrowed value would become dangling.\n\nIn PyO3 0.22.4 these functions have all been deprecated and patched to leak a\nstrong reference as a mitigation. PyO3 0.23 will remove these functions entirely.",
  "id": "RUSTSEC-2024-0378",
  "modified": "2025-10-28T06:02:18Z",
  "published": "2024-10-12T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/pyo3"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2024-0378.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/PyO3/pyo3/pull/4590"
    }
  ],
  "related": [],
  "severity": [],
  "summary": "Risk of use-after-free in `borrowed` reads from Python weak references"
}


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