CVE-2026-91921: Cross-Site Scripting (XSS) in 1millionbot’s AI chatbot platform

Severity: medium (CVSS 5.1 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-21 · updated 2026-09-22
Weakness: CWE-79

Description

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.

Affected products

1millionbot AI Chatbot Platform (SaaS) de 1millionbot.: Version prior to CVE publication

References

https://www.incibe.es/en/incibe-cert/notices/aviso/cross-site-scripting-xss-1millionbots-ai-chatbot-platform

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