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MEDIUM severity

CVE-2026-126069 — actionview

MEDIUMFix: rails/rails@9190210

CVE-2026-126069 is a medium-severity (CVSS 4.7) Cross-site Scripting (XSS) vulnerability in actionview. A fix is available for actionview — see the affected versions and patch details below.

Action View: Possible XSS vulnerability in Action View tag helpers

Also known asGHSA-68p9-83h6-5wpj
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Nov 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs15th percentile — riskier than 15% of all scored CVEsHighest risk

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
💎actionview💎actionview

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

The fix for CVE-2026-33168 skips blank HTML attribute names in Action View tag helpers, but it tests the name before converting it to a string. A Symbol name made only of whitespace, such as :" ", is not blank, because Symbol#blank? is Symbol#empty?, so it reaches the attribute escaping, which emits an attribute with no name and produces malformed HTML. The asset tag helpers, such as image_tag, video_tag and audio_tag, symbolize their options, so a whitespace String name passed to them takes the same path. A carefully crafted attribute value could then be misinterpreted by the browser as a separate attribute name, possibly leading to XSS. Applications that allow users to specify custom HTML attribute names are affected.

Releases

The fixed releases are available at the normal locations.

Patches for those who cannot upgrade at once:

Credit

This issue was responsibly reported by HackerOne researcher thepo1es.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsactionview≥ 8.1.0.beta1&&< 8.1.4.18.1.4.1bundle update actionview --conservative
💎RubyGemsactionviewall versions8.0.5.2bundle update actionview --conservative

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update actionview to 8.1.4.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-126069 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 The fix for [CVE-2026-33168](https://github.com/rails/rails/security/advisories/GHSA-v55j-83pf-r9cq) skips blank HTML attribute names in Action View tag helpers, but it tests the name before converting it to a string. A Symbol name made only of whitespace, such as `:" "`, is not blank, because `Symbol#blank?` is `Symbol#empty?`, so it reaches the attribute escaping, which emits an attribute with no name and produces malformed HTML. The asset tag helpers, such as `image_tag`, `video_tag` and `audio_tag`, symbolize their options, so a whitespace String name passed to them takes the sa
O3 Security · Impact-Aware SCA

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CVE-2026-126069: actionview XSS — Fixed in 8.1.4.1