---
id: CVE-2022-23639
aliases:
  - RUSTSEC-2022-0041
  - GHSA-qc84-gqf4-9926
title: >-
  Unsoundness of AtomicCell<*64> arithmetics on 32-bit targets that support
  Atomic*64
summary: >-
  Unsoundness of AtomicCell<*64> arithmetics on 32-bit targets that support
  Atomic*64
severity: none
vendor: crossbeam-utils
product: crossbeam-utils
ecosystem: rust
affected:
  - 'crossbeam-utils >= 0.0.0-0, < 0.8.7'
patched:
  - crossbeam-utils 0.8.7
published: '2022-02-05'
updated: '2026-07-17'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/RUSTSEC-2022-0041'
references:
  - url: 'https://crates.io/crates/crossbeam-utils'
  - url: 'https://rustsec.org/advisories/RUSTSEC-2022-0041.html'
  - url: 'https://github.com/crossbeam-rs/crossbeam/pull/781'
tags:
  - osv
  - rust
epss: 0.01239
epssPercentile: 0.67858
ingestedAt: '2026-07-17T19:00:51.820Z'
---

## Overview

## Impact

Affected versions of this crate incorrectly assumed that the alignment of {i,u}64 was always the same as Atomic{I,U}64.

However, the alignment of {i,u}64 on a 32-bit target can be smaller than Atomic{I,U}64.

This can cause the following problems:

- Unaligned memory accesses
- Data race

Crates using fetch_* methods with AtomicCell<{i,u}64> are affected by this issue.

32-bit targets without Atomic{I,U}64 and 64-bit targets are not affected by this issue.

32-bit targets with Atomic{I,U}64 and {i,u}64 have the same alignment are also not affected by this issue.

The following is a complete list of the builtin targets that may be affected. (last update: nightly-2022-02-11)

- armv7-apple-ios (tier 3)
- armv7s-apple-ios (tier 3)
- i386-apple-ios (tier 3)
- i586-unknown-linux-gnu
- i586-unknown-linux-musl
- i686-apple-darwin (tier 3)
- i686-linux-android
- i686-unknown-freebsd
- i686-unknown-haiku (tier 3)
- i686-unknown-linux-gnu
- i686-unknown-linux-musl
- i686-unknown-netbsd (tier 3)
- i686-unknown-openbsd (tier 3)
- i686-wrs-vxworks (tier 3)

([script to get list](https://gist.github.com/taiki-e/3c7891e8c5f5e0cbcb44d7396aabfe10))

## Patches

This has been fixed in crossbeam-utils 0.8.7.

Affected 0.8.x releases have been yanked.

Thanks to [@taiki-e](https://github.com/taiki-e).

## Affected packages

- `crossbeam-utils >= 0.0.0-0, < 0.8.7`

## Remediation

Upgrade to a patched release:

- `crossbeam-utils 0.8.7`