GHSA-6jwc-qr2q-7xwj
MEDIUMprotocol-http1 HTTP Request/Response Smuggling vulnerability
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
protocol-http1Real-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
RFC 9112 Section 7.1 defined the format of chunk size, chunk data and chunk extension (detailed ABNF is in Appendix section).
In summary:
- The value of Content-Length header should be a string of 0-9 digits.
- The chunk size should be a string of hex digits and should split from chunk data using CRLF.
- The chunk extension shouldn't contain any invisible character.
However, we found that Falcon has following behaviors while disobey the corresponding RFCs.
- Falcon accepts Content-Length header values that have "+" prefix.
- Falcon accepts Content-Length header values that written in hexadecimal with "0x" prefix.
- Falcon accepts "0x" and "+" prefixed chunk size.
- Falcon accepts LF in chunk extension.
This behavior can lead to desync when forwarding through multiple HTTP parsers, potentially results in HTTP request smuggling and firewall bypassing. Note that while these issues were reproduced in Falcon (the server), the issue is with protocol-http1 which implements the HTTP/1 protocol parser. We have not yet been advised of any real world exploit or practical attack.
Patches
Fixed in protocol-http1 v0.15.1+.
Workarounds
None.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | protocol-http1 | all versions | 0.15.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for protocol-http1. 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 protocol-http1 to 0.15.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6jwc-qr2q-7xwj 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-6jwc-qr2q-7xwj 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-6jwc-qr2q-7xwj. 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-6jwc-qr2q-7xwj in your dependencies?
O3 detects GHSA-6jwc-qr2q-7xwj across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.