GHSA-qc84-gqf4-9926 is a high-severity (CVSS 8.1) CWE-362 vulnerability in crossbeam-utils. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-qc84-gqf4-9926 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
crossbeam-utils Unsoundness of AtomicCell<{i,u}64> arithmetics on 32-bit targets that support Atomic{I,U}64
Real-World Exposure
crossbeam-utilsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Impact
The 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)
Patches
This has been fixed in crossbeam-utils 0.8.7.
Affected 0.8.x releases have been yanked.
References
https://github.com/crossbeam-rs/crossbeam/pull/781
License
This advisory is in the public domain.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | crossbeam-utils | all versions | 0.8.7 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for crossbeam-utils. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update crossbeam-utils to 0.8.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qc84-gqf4-9926 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-qc84-gqf4-9926 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-qc84-gqf4-9926. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-qc84-gqf4-9926 in your dependencies?
O3 detects GHSA-qc84-gqf4-9926 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.