CVE-2020-36442
HIGHCVE-2020-36442 is a high-severity (CVSS 8.1) CWE-362 vulnerability in beef. O3 Security confirms whether CVE-2020-36442 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Data races in beef
Real-World Exposure
beefReal-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
An issue was discovered in the beef crate before 0.5.0 for Rust.
Affected versions of this crate did not have a T: Sync bound in the Send impl for Cow<'_, T, U>. This allows users to create data races by making Cow contain types that are (Send && !Sync) like Cell<_> or RefCell<_>.
Such data races can lead to memory corruption.
The flaw was corrected in commit d1c7658 by adding trait bounds T: Sync and T::Owned: Send to the Send impl for Cow<'_, T, U>.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | beef | all versions | 0.5.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for beef. 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 beef to 0.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-36442 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 CVE-2020-36442 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 CVE-2020-36442. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2020-36442 in your dependencies?
O3 detects CVE-2020-36442 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.