---
id: CVE-2026-91921
title: >-
  Cross-Site Scripting (XSS) vulnerability due to inadequate input sanitisation
  in the client-side rendering engine of the 1millionbot AI Chat Platform
summary: >-
  Cross-Site Scripting (XSS) vulnerability due to inadequate input sanitisation
  in the client-side rendering engine of the 1millionbot AI Chat Platform. An
  unauthenticated remote user could cause external hyperlinks to be rendered in
  the w…
severity: medium
cvss: 5.1
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N'
cwe:
  - CWE-79
vendor: 1millionbot
product: AI Chatbot Platform (SaaS) de 1millionbot.
affected:
  - ai_chatbot_platform_saas_de_1millionbot. Version prior to CVE publication
published: '2026-09-21'
updated: '2026-09-22'
sourceUpdated: '2026-09-22T19:41:38.447'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-91921'
references:
  - url: >-
      https://www.incibe.es/en/incibe-cert/notices/aviso/cross-site-scripting-xss-1millionbots-ai-chatbot-platform
    label: cve-coordination@incibe.es
tags:
  - nvd
  - cve.org
epss: 0.00596
epssPercentile: 0.46311
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-21T11:12:34.390647Z'
cvssSource: cna
ingestedAt: '2026-09-21T10:35:15.459Z'
---

## Overview

Cross-Site Scripting (XSS) vulnerability due to inadequate input sanitisation in the client-side rendering engine of the 1millionbot AI Chat Platform. An unauthenticated remote user could cause external hyperlinks to be rendered in the web interface by sending messages containing Markdown syntax and certain unsanitised content blocks. The impact is limited to the user’s own interactive session; no compromise of internal infrastructure, access to third-party data or impact on administrative panels has been identified.

## Remediation

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