GHSA-g6wq-qcwm-j5g2 is a high-severity (CVSS 8.2) vulnerability in websocket-extensions. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-g6wq-qcwm-j5g2 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Regular Expression Denial of Service in websocket-extensions (RubyGem)
Real-World Exposure
websocket-extensionsReal-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
The ReDoS flaw allows an attacker to exhaust the server's capacity to process incoming requests by sending a WebSocket handshake request containing a header of the following form:
Sec-WebSocket-Extensions: a; b="\c\c\c\c\c\c\c\c\c\c ...
That is, a header containing an unclosed string parameter value whose content is a repeating two-byte sequence of a backslash and some other character. The parser takes exponential time to reject this header as invalid, and this will block the processing of any other work on the same thread. Thus if you are running a single-threaded server, such a request can render your service completely unavailable.
Patches
Users should upgrade to version 0.1.5.
Workarounds
There are no known work-arounds other than disabling any public-facing WebSocket functionality you are operating.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | websocket-extensions | all versions | 0.1.5 |
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 websocket-extensions. 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 websocket-extensions to 0.1.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g6wq-qcwm-j5g2 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-g6wq-qcwm-j5g2 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-g6wq-qcwm-j5g2. 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.
Red Hat CloudForms 4.7 (CFME 5.10) is in the maintenance phase and we will not be fixing Medium/Low impact security bugs. Reference: https://access.redhat.com/support/policy/updates/cloudforms Red Hat Satellite 6 ships affected RubyGem Websocket-extensions, however, product is not vulnerable to the flaw. A future…
Frequently Asked Questions
Is GHSA-g6wq-qcwm-j5g2 in your dependencies?
O3 detects GHSA-g6wq-qcwm-j5g2 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.