GHSA-x7jg-6pwg-fx5h is a high-severity (CVSS 7.5) CWE-444 vulnerability in puma. O3 Security confirms whether GHSA-x7jg-6pwg-fx5h is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
HTTP Smuggling via Transfer-Encoding Header in Puma
Real-World Exposure
puma💎pumaReal-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
Impact
By using an invalid transfer-encoding header, an attacker could smuggle an HTTP response.
Originally reported by @ZeddYu, who has our thanks for the detailed report.
Patches
The problem has been fixed in Puma 3.12.5 and Puma 4.3.4.
For more information
If you have any questions or comments about this advisory:
- Open an issue in Puma
- See our security policy
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | puma | all versions | 3.12.5 |
| 💎RubyGems | puma | ≥ 4.0.0&&< 4.3.4 | 4.3.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for puma. 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 puma to 3.12.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-x7jg-6pwg-fx5h 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 GHSA-x7jg-6pwg-fx5h 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 GHSA-x7jg-6pwg-fx5h. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-x7jg-6pwg-fx5h in your dependencies?
O3 detects GHSA-x7jg-6pwg-fx5h across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.