rustsec-2026-0156
Vulnerability from osv_rustsec
Published
2026-06-01 12:00
Modified
2026-06-03 10:42
Summary
Bad-free in `MetaCallException::new`
Details

exception_struct is a local stack variable, but the code passes its address to the C language as &mut exception_struct as *mut _ as *mut c_void. Then, the returned MetaCallException value is stored here:

Ok(Self {
    exception_struct: Arc::new(exception_struct),
    value: exception_ptr,
    leak: false,
})

Because leak is false, the destructor will run later. But the original exception pointer points to Rust stack memory.

Trigger

#[test]
fn exception_bad_free_safe_api() {
    let original = metacall::MetaCallException::new(
        "test",
        "test",
        "test",
        1,
    );

    drop(original); // AddressSanitizer: bad-free
}

Impact

Every time the MetaCallException is created, when it is dropped, it leads to a bad-free. This can be triggered through the safe public API MetaCallException::new(), with no unsafe required from the caller.

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "memory-corruption"
        ],
        "cvss": null,
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "metacall",
        "purl": "pkg:cargo/metacall"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.0.0-0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "`exception_struct` is a local stack variable, but the code passes its address to the C language as `\u0026mut exception_struct as *mut _ as *mut c_void`. Then, the returned `MetaCallException` value is stored here:\n```rust\nOk(Self {\n    exception_struct: Arc::new(exception_struct),\n    value: exception_ptr,\n    leak: false,\n})\n```\nBecause leak is false, the destructor will run later. But the original exception pointer points to Rust stack memory.\n\n## Trigger\n\n```rust\n#[test]\nfn exception_bad_free_safe_api() {\n    let original = metacall::MetaCallException::new(\n        \"test\",\n        \"test\",\n        \"test\",\n        1,\n    );\n\n    drop(original); // AddressSanitizer: bad-free\n}\n```\n\n## Impact\n\nEvery time the `MetaCallException` is created, when it is dropped, it leads to a bad-free. This can be triggered through the safe public API `MetaCallException::new()`, with no `unsafe` required from the caller.",
  "id": "RUSTSEC-2026-0156",
  "modified": "2026-06-03T10:42:03Z",
  "published": "2026-06-01T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/metacall"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0156.html"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/metacall/core/issues/809"
    }
  ],
  "related": [],
  "severity": [],
  "summary": "Bad-free in `MetaCallException::new`"
}


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