How severe is CVE-2024-21636?

CVE-2024-21636 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2024-21636?

CVE-2024-21636 affects the following packages: view_component (RubyGems), view_component (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2024-21636?

Update view_component to 3.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21636 is resolved across your whole dependency graph.

How do I detect CVE-2024-21636 in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for view_component. 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.

How do I mitigate CVE-2024-21636 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2024-21636?

O3 pinpoints whether CVE-2024-21636 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2024-21636 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2024-21636, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2024-21636?

CVE-2024-21636 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 39th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2024-21636?

CVE-2024-21636 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2024-21636 published, and has it been updated?

CVE-2024-21636 was published on January 4, 2024 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎 RubyGems

CVE-2024-21636

MEDIUM

view_component Cross-site Scripting vulnerability

Also known asGHSA-wf2x-8w6j-qw37

Published

Jan 4, 2024

Updated

Apr 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

1 known

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk39th percentile-0.01%

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

2 pkgs affected

💎view_component💎view_component

Real-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

view_component is a framework for building reusable, testable, and encapsulated view components in Ruby on Rails. Versions prior to 3.9.0 and 2.83.0 have a cross-site scripting vulnerability that has the potential to impact anyone rendering a component directly from a controller with the view_component gem. Note that only components that define a #call method (i.e. instead of using a sidecar template) are affected. The return value of the #call method is not sanitized and can include user-defined content. In addition, the return value of the #output_postamble methodis not sanitized, which can also lead to cross-site scripting issues. Versions 3.9.0 and 2.83.0 have been released and fully mitigate both the #call and the #output_postamble vulnerabilities. As a workaround, sanitize the return value of #call.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`view_component`	≥ 3.0.0&&< 3.9.0	3.9.0
💎RubyGems	`view_component`	all versions	2.83.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

view_component is a framework for building reusable, testable, and encap…

github.comNVDJan 2024

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for view_component. 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 view_component to 3.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21636 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-2024-21636 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-2024-21636. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

view_component is a framework for building reusable, testable, and encapsulated view components in Ruby on Rails. Versions prior to 3.9.0 and 2.83.0 have a cross-site scripting vulnerability that has the potential to impact anyone rendering a component directly from a controller with the view_component gem. Note that only components that define a `#call` method (i.e. instead of using a sidecar template) are affected. The return value of the `#call` method is not sanitized and can include user-defined content. In addition, the return value of the `#output_postamble` methodis not sanitized, whic

O3 Security · Impact-Aware SCA

Is CVE-2024-21636 in your dependencies?

O3 detects CVE-2024-21636 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works