CVE-2026-30821

Estado: AnalizadaAlta (8.2)—

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to version 3.0.13, the /api/v1/attachments/:chatflowId/:chatId endpoint is listed in WHITELIST_URLS, allowing unauthenticated access to the file upload API. While the server validates uploads based on the MIME types defined in chatbotConfig.fullFileUpload.allowedUploadFileTypes, it implicitly trusts the client-provided Content-Type header (file.mimetype) without verifying the file's actual content (magic bytes) or extension (file.originalname).

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Consequently, an attacker can bypass this restriction by spoofing the Content-Type as a permitted type (e.g., application/pdf) while uploading malicious scripts or arbitrary files. Once uploaded via addArrayFilesToStorage, these files persist in backend storage (S3, GCS, or local disk). This vulnerability serves as a critical entry point that, when chained with other features like static hosting or file retrieval, can lead to Stored XSS, malicious file hosting, or Remote Code Execution (RCE). This issue has been patched in version 3.0.13.

CVSS

Versión: 4.0
Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/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: 8.2

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.93%
Percentil entre todas las CVEs puntuadas: 59
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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access60 %
Impacto principalT1505.003 Web Shellpersistence55 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability Scanning User Account Management Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic

Tecnologías afectadas (1)

Flowiseai — Flowise

CWE

CWE-434

Referencias

JSON original (NVD)

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      "value": "Flowise is a drag & drop user interface to build a customized large language model flow. Prior to version 3.0.13, the /api/v1/attachments/:chatflowId/:chatId endpoint is listed in WHITELIST_URLS, allowing unauthenticated access to the file upload API. While the server validates uploads based on the MIME types defined in chatbotConfig.fullFileUpload.allowedUploadFileTypes, it implicitly trusts the client-provided Content-Type header (file.mimetype) without verifying the file's actual content (magic bytes) or extension (file.originalname). Consequently, an attacker can bypass this restriction by spoofing the Content-Type as a permitted type (e.g., application/pdf) while uploading malicious scripts or arbitrary files. Once uploaded via addArrayFilesToStorage, these files persist in backend storage (S3, GCS, or local disk). This vulnerability serves as a critical entry point that, when chained with other features like static hosting or file retrieval, can lead to Stored XSS, malicious file hosting, or Remote Code Execution (RCE). This issue has been patched in version 3.0.13."
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      "value": "Flowise es una interfaz de usuario de arrastrar y soltar para construir un flujo de modelo de lenguaje grande personalizado. Antes de la versión 3.0.13, el endpoint /api/v1/attachments/:chatflowId/:chatId está listado en WHITELIST_URLS, permitiendo acceso no autenticado a la API de carga de archivos. Aunque el servidor valida las cargas basándose en los tipos MIME definidos en chatbotConfig.fullFileUpload.allowedUploadFileTypes, confía implícitamente en el encabezado Content-Type proporcionado por el cliente (file.mimetype) sin verificar el contenido real del archivo (bytes mágicos) o la extensión (file.originalname). En consecuencia, un atacante puede eludir esta restricción falsificando el Content-Type como un tipo permitido (p. ej., application/pdf) mientras carga scripts maliciosos o archivos arbitrarios. Una vez cargados a través de addArrayFilesToStorage, estos archivos persisten en el almacenamiento de backend (S3, GCS o disco local). Esta vulnerabilidad sirve como un punto de entrada crítico que, cuando se encadena con otras características como el alojamiento estático o la recuperación de archivos, puede conducir a XSS Almacenado, alojamiento de archivos maliciosos o Ejecución Remota de Código (RCE). Este problema ha sido parcheado en la versión 3.0.13."
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  "lastModified": "2026-06-17T10:32:58.443",
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