GHSA-w67g-2h6v-vjgq is a high-severity (CVSS 7.1) vulnerability in phlex. A fix is available for phlex — see the affected versions and patch details below.
Phlex XSS protection bypass via attribute splatting, dynamic tags, and href values
Real-World Exposure
phlex💎phlex💎phlex💎phlex💎phlex💎phlexReal-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
During a security audit conducted with Claude Opus 4.6 and GPT-5.3-Codex, we identified three specific ways to bypass the XSS (cross-site-scripting) protection built into Phlex.
- The first bypass could happen if user-provided attributes with string keys were splatted into HTML tag, e.g.
div(**user_attributes). - The second bypass could happen if user-provided tag names were passed to the
tagmethod, e.g.tag(some_tag_name_from_user). - The third bypass could happen if user’s links were passed to
hrefattributes, e.g.a(href: user_provided_link).
All three of these patterns are meant to be safe and all have now been patched.
Patches
Phlex has patched all three issues and introduced new tests that run against Safari, Firefox and Chrome.
The patched versions are:
Phlex has also patched the main branch in GitHub.
Workarounds
If a project uses a secure CSP (content security policy) or if the application doesn’t use any of the above patterns, it is not at risk.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | phlex | ≥ 2.4.0.beta1&&< 2.4.1 | 2.4.1bundle update phlex --conservative |
| 💎RubyGems | phlex | ≥ 2.3.0&&< 2.3.2 | 2.3.2bundle update phlex --conservative |
| 💎RubyGems | phlex | ≥ 2.2.0&&< 2.2.2 | 2.2.2bundle update phlex --conservative |
| 💎RubyGems | phlex | ≥ 2.1.0&&< 2.1.3 | 2.1.3bundle update phlex --conservative |
| 💎RubyGems | phlex | ≥ 2.0.0.beta1&&< 2.0.2 | 2.0.2bundle update phlex --conservative |
| 💎RubyGems | phlex | all versions | 1.11.1bundle update phlex --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phlex, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update phlex to 2.4.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w67g-2h6v-vjgq 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-w67g-2h6v-vjgq can be triaged on real exposure rather than presence alone.
Tailored to GHSA-w67g-2h6v-vjgq. 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-w67g-2h6v-vjgq in your dependencies?
O3 Security finds GHSA-w67g-2h6v-vjgq across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.