CVE-2020-8184
HIGHCVE-2020-8184 is a high-severity (CVSS 7.5) CWE-784 vulnerability in rack. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2020-8184 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Rack allows Percent-encoded cookies to overwrite existing prefixed cookie names
Real-World Exposure
rack💎rackReal-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
A reliance on cookies without validation/integrity check security vulnerability exists in rack < 2.2.3, rack < 2.1.4 that makes it is possible for an attacker to forge a secure or host-only cookie prefix.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | rack | all versions | 2.1.4 |
| 💎RubyGems | rack | ≥ 2.2.0&&< 2.2.3 | 2.2.3 |
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 rack. 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 rack to 2.1.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-8184 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-2020-8184 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-2020-8184. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Because Red Hat OpenStack Platform 13.0 Operational Tools packages ships the flawed code, but does not use its functionality, its Impact has been reduced to 'Low'. Red Hat Satellite 6 and Red Hat CloudForms ship affected RubyGem Rack, however, since overwriting cookies is not possible products are not vulnerable to…
Frequently Asked Questions
Is CVE-2020-8184 in your dependencies?
O3 detects CVE-2020-8184 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.