---
id: CVE-2026-73428
title: Trix is a what-you-see-is-what-you-get rich text editor for everyday writing
summary: >-
  Trix is a what-you-see-is-what-you-get rich text editor for everyday writing.
  Prior to 2.1.18, Trix is vulnerable to stored cross-site scripting when
  crafted HTML is pasted into the editor. HTMLParser processes a mock attachment
  in a `<s…
severity: medium
cvss: 4.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N'
cwe:
  - CWE-79
published: '2026-08-13'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T20:09:01.757'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73428'
references:
  - url: >-
      https://github.com/basecamp/trix/commit/9c0a993d9fc2ffe9d56b013b030bc238f9c0557c
    label: security-advisories@github.com
  - url: 'https://github.com/basecamp/trix/pull/1293'
    label: security-advisories@github.com
  - url: 'https://github.com/basecamp/trix/releases/tag/v2.1.18'
    label: security-advisories@github.com
  - url: 'https://github.com/basecamp/trix/security/advisories/GHSA-53g2-mvcc-q9x3'
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00353
epssPercentile: 0.2622
ingestedAt: '2026-09-18T20:51:25.613Z'
---

## Overview

Trix is a what-you-see-is-what-you-get rich text editor for everyday writing. Prior to 2.1.18, Trix is vulnerable to stored cross-site scripting when crafted HTML is pasted into the editor. HTMLParser processes a mock attachment in a `<span>` with an empty `data-trix-attachment="{}"` value, causing data-trix-attributes to be applied to a plain string piece. StringPiece.fromJSON accepts an unvalidated href, allowing a javascript: URI to enter the document model and serialized HTML and execute when another user renders and clicks the content. Applications that apply server-side HTML sanitization can neutralize the payload on save. This issue is fixed in version 2.1.18.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.