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MEDIUM severity

view_component Cross-site Scripting vulnerabilityGHSA-wf2x-8w6j-qw37

MEDIUMFix: ViewComponent/view_component#1950

GHSA-wf2x-8w6j-qw37 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in view_component. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for view_component — see the affected versions and patch details below.

Also known asCVE-2024-21636
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
1 known
Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-wf2x-8w6j-qw37.

EPSS Exploitation Probability

via FIRST.org ↗
0.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs43th percentile — riskier than 43% of all scored CVEsHighest risk
0.00%0.33%0.67%1.00%0.5%0.5%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

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

Impact

What kind of vulnerability is it? Who is impacted?

This is an XSS 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 method is not sanitized, which can also lead to XSS issues.

Patches

Has the problem been patched? What versions should users upgrade to?

Versions 3.9.0 has been released and fully mitigates both the #call and the #output_postamble vulnerabilities.

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

Sanitize the return value of #call, eg:

class MyComponent < ApplicationComponent
  def call
    html_escape("<div>#{user_input}</div>")
  end
end

References

Are there any links users can visit to find out more?

https://github.com/ViewComponent/view_component/pull/1950

For more information

If you have any questions or comments about this advisory:

Open an issue in the github/view_component project.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsview_component≥ 3.0.0&&< 3.9.03.9.0bundle update view_component --conservative
💎RubyGemsview_componentall versions2.83.0bundle update view_component --conservative

Affected Products

1 product · 2 configurations
Application
view componentviewcomponent
≥ 3.0.0 && < 3.9.0
range
Exploits & PoCs
1

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 dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for view_component, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update view_component to 3.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wf2x-8w6j-qw37 is resolved across your whole dependency graph.

  3. Workarounds

    Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### Impact _What kind of vulnerability is it? Who is impacted?_ This is an XSS 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](https://viewcomponent.org/guide/templates.html#call) (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` method](https://viewcomponent.org/api.html#output_postamble--string)
O3 Security · Impact-Aware SCA

Is GHSA-wf2x-8w6j-qw37 in your dependencies?

Find it across RubyGems, including transitive dependencies.

view_component Cross-site Scripting vulnerability