crossbeam-channel Undefined Behavior before v0.4.4GHSA-v5m7-53cv-f3hx
HIGHFix: RustSec/advisory-db#425GHSA-v5m7-53cv-f3hx is a high-severity (CVSS 8.1) Buffer Overflow vulnerability in crossbeam-channel. 2 public exploit references exist, so weaponization risk is real. A fix is available for crossbeam-channel — see the affected versions and patch details below.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-v5m7-53cv-f3hx by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
crossbeam-channelReal-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 version of this crate's the bounded channel incorrectly assumes that Vec::from_iter has allocated capacity that same as the number of iterator elements. Vec::from_iter does not actually guarantee that and may allocate extra memory. The destructor of the bounded channel reconstructs Vec from the raw pointer based on the incorrect assumes described above. This is unsound and causing deallocation with the incorrect capacity when Vec::from_iter has allocated different sizes with the number of iterator elements.
Patches
This has been fixed in crossbeam-channel 0.4.4.
We recommend users to upgrade to 0.4.4.
References
See https://github.com/crossbeam-rs/crossbeam/pull/533, https://github.com/crossbeam-rs/crossbeam/issues/539, and https://github.com/RustSec/advisory-db/pull/425 for more details.
License
This advisory is in the public domain.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | crossbeam-channel | ≥ 0.4.3&&< 0.4.4 | 0.4.4cargo update -p crossbeam-channel --precise 0.4.4 |
Affected Products
crossbeamcrossbeam_projectResearch 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-channel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update crossbeam-channel to 0.4.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v5m7-53cv-f3hx is resolved across your whole dependency graph.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.
Frequently Asked Questions
Is GHSA-v5m7-53cv-f3hx in your dependencies?
Find it across crates.io, including transitive dependencies.