CVE-2020-36327
HIGHCVE-2020-36327 is a high-severity (CVSS 8.8) vulnerability in bundler. 2 public exploit references exist, so weaponization risk is real. O3 Security confirms whether CVE-2020-36327 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Dependency Confusion in Bundler
Blast Radius
bundler💎bundlerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Bundler 1.16.0 through 2.2.9 and 2.2.11 through 2.2.16 sometimes chooses a dependency source based on the highest gem version number, which means that a rogue gem found at a public source may be chosen, even if the intended choice was a private gem that is a dependency of another private gem that is explicitly depended on by the application. NOTE: it is not correct to use CVE-2021-24105 for every "Dependency Confusion" issue in every product.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | bundler | ≥ 1.16.0&&< 2.2.10 | 2.2.10 |
| 💎RubyGems | bundler | ≥ 2.2.11&&< 2.2.18 | 2.2.18 |
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 bundler. 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 bundler to 2.2.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-36327 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-2020-36327 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-2020-36327. 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-2020-36327 in your dependencies?
O3 detects CVE-2020-36327 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.