CVE-2020-36447 is a high-severity (CVSS 8.1) CWE-362 vulnerability in v9. 1 public exploit reference exists, so weaponization risk is real. A fix is available for v9 — see the affected versions and patch details below.
Data race in v9
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2020-36447 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
v9Real-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 implement Sync for SyncRef<T>. This definition allows data races if &T is accessible through &SyncRef.
SyncRef<T> derives Clone and Debug, and the default implementations of those traits access &T by invoking T::clone() & T::fmt(). It is possible to create data races & undefined behavior by concurrently invoking SyncRef<T>::clone() or SyncRef<T>::fmt() from multiple threads with T: !Sync.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | v9 | all versions | 0.1.43cargo update -p v9 --precise 0.1.43 |
Affected Products
v9v9_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 v9, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update v9 to 0.1.43 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-36447 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.
Frequently Asked Questions
Is CVE-2020-36447 in your dependencies?
Find it across crates.io, including transitive dependencies.