CVE-2020-36469
MEDIUMCVE-2020-36469 is a medium-severity (CVSS 5.9) vulnerability in appendix. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2020-36469 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Data races in appendix
Real-World Exposure
appendixReal-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
The appendix crate implements a key-value mapping data structure called
Index<K, V> that is stored on disk. The crate allows for any type to inhabit
the generic K and V type parameters and implements Send and Sync for them
unconditionally.
Using a type that is not marked as Send or Sync with Index can allow it
to be used across multiple threads leading to data races. Additionally using
reference types for the keys or values will lead to the segmentation faults
in the crate's code.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | appendix | all versions | No fix |
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 appendix. 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.
Remediation status
No patched version of appendix has shipped for CVE-2020-36469 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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-2020-36469 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-2020-36469. 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-2020-36469 in your dependencies?
O3 detects CVE-2020-36469 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.