rustsec-2026-0221
Vulnerability from osv_rustsec
Published
2026-07-13 12:00
Modified
2026-07-31 12:11
Summary
`event-listener` allows `!Send` tags to cross thread boundaries via `StackSlot`
Details

Affected versions of event-listener unconditionally implement Send and Sync for StackSlot<'_, T>, the stack-allocated listener type created by the listener! macro.

This allows a !Send tag type set via Event::with_tag to be moved to another thread and accessed via StackSlot::wait, causing a data race in safe code.

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "memory-corruption",
          "thread-safety"
        ],
        "cvss": null,
        "informational": "unsound"
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "event-listener",
        "purl": "pkg:cargo/event-listener"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.1.0"
            },
            {
              "fixed": "5.4.2"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "Affected versions of `event-listener` unconditionally implement `Send` and\n`Sync` for `StackSlot\u003c\u0027_, T\u003e`, the stack-allocated listener type created\nby the `listener!` macro.\n\nThis allows a `!Send` tag type set via `Event::with_tag` to be moved to\nanother thread and accessed via `StackSlot::wait`, causing a data race in safe\ncode.",
  "id": "RUSTSEC-2026-0221",
  "modified": "2026-07-31T12:11:10Z",
  "published": "2026-07-13T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/event-listener"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0221.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/smol-rs/event-listener/pull/163"
    }
  ],
  "related": [],
  "severity": [],
  "summary": "`event-listener` allows `!Send` tags to cross thread boundaries via `StackSlot`"
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • 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.
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  • 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.