GHSA-vfpf-xmwh-8m65

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Source
https://github.com/advisories/GHSA-vfpf-xmwh-8m65
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/11/GHSA-vfpf-xmwh-8m65/GHSA-vfpf-xmwh-8m65.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-vfpf-xmwh-8m65
Withdrawn
2025-11-10T15:37:06Z
Published
2025-11-07T23:17:31Z
Modified
2025-11-10T15:55:21Z
Severity
  • 7.6 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N CVSS Calculator
Summary
Duplicate Advisory: ProsemirrorToHtml has a Cross-Site Scripting (XSS) vulnerability through unescaped HTML attribute values
Details

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-52c5-vh7f-26fx. This link is maintained to preserve external references.

Original Description

Impact

The prosemirror_to_html gem is vulnerable to Cross-Site Scripting (XSS) attacks through malicious HTML attribute values. While tag content is properly escaped, attribute values are not, allowing attackers to inject arbitrary JavaScript code.

Who is impacted:

  • Any application using prosemirror_to_html to convert ProseMirror documents to HTML
  • Applications that process user-generated ProseMirror content are at highest risk
  • End users viewing the rendered HTML output could have malicious JavaScript executed in their browsers

Attack vectors include:

  • href attributes with javascript: protocol: <a href="javascript:alert(document.cookie)">
  • Event handlers: <div onclick="maliciousCode()">
  • onerror attributes on images: <img src=x onerror="alert('XSS')">
  • Other HTML attributes that can execute JavaScript

Patches

A fix is currently in development. Users should upgrade to version 0.2.1 or later once released.

The patch escapes all HTML attribute values using CGI.escapeHTML to prevent injection attacks.

Workarounds

Until a patched version is available, users can implement one or more of these mitigations:

  1. Sanitize output: Pass the HTML output through a sanitization library like Sanitize or Loofah:
   html = ProsemirrorToHtml.render(document)
   safe_html = Sanitize.fragment(html, Sanitize::Config::RELAXED)
  1. Implement Content Security Policy (CSP): Add strict CSP headers to prevent inline JavaScript execution:
   Content-Security-Policy: default-src 'self'; script-src 'self'
  1. Input validation: If possible, validate and sanitize ProseMirror documents before conversion to prevent malicious content from entering the system.

References

Database specific 
{
    "cwe_ids": [
        "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-11-07T23:17:31Z",
    "nvd_published_at": null,
    "severity": "HIGH"
}
References

Affected packages

RubyGems / prosemirror_to_html

Package

Name
prosemirror_to_html
Purl
pkg:gem/prosemirror_to_html

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
0.2.1

Affected versions

0.*
0.1.0
0.2.0

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/11/GHSA-vfpf-xmwh-8m65/GHSA-vfpf-xmwh-8m65.json"