CVE-2020-36439 is a high-severity (CVSS 8.1) CWE-362 vulnerability in ticketed_lock. O3 Security confirms whether CVE-2020-36439 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Data races in ticketed_lock
Real-World Exposure
ticketed_lockReal-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
Affected versions of this crate unconditionally implemented Send for ReadTicket<T> & WriteTicket<T>. This allows to send non-Send T to other threads. This can allows creating data races by cloning types with internal mutability and sending them to other threads (as T of ReadTicket<T>/WriteTicket<T>). Such data races can cause memory corruption or other undefined behavior. The flaw was corrected in commit a986a93 by adding T: Send bounds to Send impls of ReadTicket<T>/WriteTicket<T>.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | ticketed_lock | all versions | 0.3.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ticketed_lock. 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 ticketed_lock to 0.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-36439 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-2020-36439 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-2020-36439. 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-2020-36439 in your dependencies?
O3 detects CVE-2020-36439 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.