CVE-2020-35874
HIGHCVE-2020-35874 is a high-severity (CVSS 8.1) CWE-362 vulnerability in internment. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2020-35874 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Use after free in internment
Real-World Exposure
internmentReal-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
ArcIntern::drop has a race condition where it can release memory which is about to get another user. The new user will get a reference to freed memory.
This was fixed by serializing access to an interned object while it is being deallocated.
Versions prior to 0.3.12 used stronger locking which avoided the problem.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | internment | ≥ 0.3.12&&< 0.4.0 | 0.4.0 |
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 internment. 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 internment to 0.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-35874 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-2020-35874 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-2020-35874. 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-2020-35874 in your dependencies?
O3 detects CVE-2020-35874 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.