CVE-2024-28199
HIGHCross-site Scripting (XSS) possible with maliciously formed HTML attribute names and values in Phlex
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
phlex💎phlex💎phlex💎phlex💎phlex💎phlex💎phlex💎phlex+2 moreReal-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
phlex is an open source framework for building object-oriented views in Ruby. There is a potential cross-site scripting (XSS) vulnerability that can be exploited via maliciously crafted user data. This was due to improper case-sensitivity in the code that was meant to prevent these attacks. If you render an <a> tag with an href attribute set to a user-provided link, that link could potentially execute JavaScript when clicked by another user. If you splat user-provided attributes when rendering any HTML tag, malicious event attributes could be included in the output, executing JavaScript when the events are triggered by another user. Patches are available on RubyGems for all 1.x minor versions. Users are advised to upgrade. Users unable to upgrade should consider configuring a content security policy that does not allow unsafe-inline.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | phlex | ≥ 1.9.0&&< 1.9.1 | 1.9.1 |
| 💎RubyGems | phlex | ≥ 1.8.0&&< 1.8.2 | 1.8.2 |
| 💎RubyGems | phlex | ≥ 1.7.0&&< 1.7.1 | 1.7.1 |
| 💎RubyGems | phlex | ≥ 1.6.0&&< 1.6.2 | 1.6.2 |
| 💎RubyGems | phlex | ≥ 1.5.0&&< 1.5.2 | 1.5.2 |
| 💎RubyGems | phlex | ≥ 1.4.0&&< 1.4.1 | 1.4.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phlex. 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 phlex to 1.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-28199 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-2024-28199 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-2024-28199. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-28199 in your dependencies?
O3 detects CVE-2024-28199 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.