CVE-2026-91921
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.
CVSS
- Versión: 4.0
- Vector: 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Puntuación base: 5.1
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.60%
- Percentil entre todas las CVEs puntuadas: 47
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1189Drive-by Compromiseinitial access92 % - Impacto principal
T1059.007JavaScriptexecution45 %
XSS en plataforma web (CWE-79) con AV:N/UI:A sugiere drive-by (T1189). T1059.007 por potencial ejecución JavaScript, pero confianza baja: texto limita impacto a sesión del usuario.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-79
Referencias
JSON original (NVD)
Mostrar
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"id": "CVE-2026-91921",
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"id": "CVE-2026-91921",
"role": "CISA Coordinator",
"options": [
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"timestamp": "2026-09-21T11:12:34.390647Z"
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"affected": [
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"affectedData": [
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"vendor": "1millionbot",
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"versions": [
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"published": "2026-09-21T10:17:15.873",
"references": [
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"url": "https://www.incibe.es/en/incibe-cert/notices/aviso/cross-site-scripting-xss-1millionbots-ai-chatbot-platform",
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"description": [
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"value": "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."
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"lastModified": "2026-09-22T19:41:38.447",
"sourceIdentifier": "cve-coordination@incibe.es"
}