CVE-2026-73427: Trix Cross-Site Scripting Vulnerability

LOW
Advisory Identifier: GHSA-53p3-c7vp-4mcc
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CWE-79
Published
Advisory Summary

CVE-2026-73427 is a LOW cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Trix libraries in the npm ecosystem. The issue involves trix is vulnerable to xss through json deserialization bypass in drag-and-drop (level0inputcontroller). Remediation is available by upgrading affected packages to version 2.1.18.

CVE-2026-73427 at a Glance

CVE Identifier CVE-2026-73427
GHSA Identifier GHSA-53p3-c7vp-4mcc
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Trix
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-73427

To remediate this vulnerability, upgrade all affected Trix dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

trix fixed: 2.1.18 
npm install trix@2.1.18
action_text-trix fixed: 2.1.18 
Upgrade action_text-trix to 2.1.18
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls trix

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-73427, inspect your project dependencies using npm:

npm ls trix

Analyze the terminal output to locate any version of Trix in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.1.18), your application is affected.

Note: The npm ls trix command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Trix, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact The Trix editor, in versions prior to 2.1.18, is vulnerable to XSS when a crafted `application/x-trix-document` JSON payload is dropped into the editor in environments using the fallback Level0InputController (e.g., embedded WebViews lacking Input Events Level 2 support). The `StringPiece.fromJSON` method trusted `href` attributes from the JSON payload without sanitization. An attacker could craft a draggable element containing a `javascript:` URI in the href attribute that, when dropped into a vulnerable editor, would bypass DOMPurify sanitization and inject executable JavaScript into the DOM. Exploitation requires a specific environment (Level0InputController fallback) and social engineering (victim must drag and drop attacker-controlled content into the editor). Applications using server-side HTML sanitization (such as Rails' built-in sanitizer) are additionally protected, as the payload is neutralized on save. ### Patches Update Recommendation: Users should upgrade to Trix editor version 2.1.18 or later. ### References The XSS vulnerability was responsibly reported by Hackerone researcher [newbiefromcoma](https://hackerone.com/newbiefromcoma).

CVE-2026-73427 Affected Trix Versions

2 component(s)
Fixed Versions:
2.1.18
Product / Package Ecosystem Affected Versions Fixed Version
trix
npm/trix
npm
< 2.1.18
2.1.18
action_text-trix
gem/action_text-trix
RubyGems
< 2.1.18
2.1.18

References

GitHub Advisory / Wiki ADVISORY
https://github.com/basecamp/trix/security/advisories/GHSA-53p3-c7vp-4mcc
Security Fix Commit FIX COMMIT
https://github.com/basecamp/trix/commit/9c0a993d9fc2ffe9d56b013b030bc238f9c0557c
Trix Source Repository REPOSITORY
https://github.com/basecamp/trix
Trix Release RELEASE
https://github.com/basecamp/trix/releases/tag/v2.1.18
Trix Source Repository REPOSITORY
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/action_text-trix/GHSA-53p3-c7vp-4mcc.yml

Frequently Asked Questions

What is CVE-2026-73427?
CVE-2026-73427 is a security vulnerability in Trix involving Trix is vulnerable to XSS through JSON deserialization bypass in drag-and-drop (Level0InputController) under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Trix versions are affected?
Affected versions include releases prior to 2.1.18 across affected packages: trix, action_text-trix.
What version fixes CVE-2026-73427?
Upgrading to 2.1.18 (or the latest patched release for your respective branch) resolves the vulnerability.
Is trix affected?
Yes, trix is affected in releases prior to 2.1.18. Upgrade your dependency to 2.1.18 or later.
Is action_text-trix affected?
Yes, action_text-trix is affected in releases prior to 2.1.18. Upgrade your dependency to 2.1.18 or later.
What CWE is associated with CVE-2026-73427?
CVE-2026-73427 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check npm dependencies for CVE-2026-73427?
Run the dependency tree command: 'npm ls trix'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-53p3-c7vp-4mcc",
  "modified" : "2026-08-12T20:50:23Z",
  "published" : "2026-03-29T15:22:17Z",
  "aliases" : [ "CVE-2026-73427" ],
  "summary" : "Trix is vulnerable to XSS through JSON deserialization bypass in drag-and-drop (Level0InputController)",
  "details" : "### Impact\n\nThe Trix editor, in versions prior to 2.1.18, is vulnerable to XSS when a crafted `application/x-trix-document` JSON payload is dropped into the editor in environments using the fallback Level0InputController (e.g., embedded WebViews lacking Input Events Level 2 support).\n\nThe `StringPiece.fromJSON` method trusted `href` attributes from the JSON payload without sanitization. An attacker could craft a draggable element containing a `javascript:` URI in the href attribute that, when dropped into a vulnerable editor, would bypass DOMPurify sanitization and inject executable JavaScript into the DOM.\n\nExploitation requires a specific environment (Level0InputController fallback) and social engineering (victim must drag and drop attacker-controlled content into the editor). Applications using server-side HTML sanitization (such as Rails' built-in sanitizer) are additionally protected, as the payload is neutralized on save.\n\n### Patches\n\nUpdate Recommendation: Users should upgrade to Trix editor version 2.1.18 or later.\n\n\n### References\n\nThe XSS vulnerability was responsibly reported by Hackerone researcher [newbiefromcoma](https://hackerone.com/newbiefromcoma).",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "trix"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.1.18"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "action_text-trix"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.1.18"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/basecamp/trix/security/advisories/GHSA-53p3-c7vp-4mcc"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/basecamp/trix/commit/9c0a993d9fc2ffe9d56b013b030bc238f9c0557c"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/basecamp/trix"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/basecamp/trix/releases/tag/v2.1.18"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/action_text-trix/GHSA-53p3-c7vp-4mcc.yml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-29T15:22:17Z",
    "nvd_published_at" : null
  }
}