CVE-2026-27804

Estado: AnalizadaCrítica (9.3)—

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.3 and 9.1.1-alpha.4, an unauthenticated attacker can forge a Google authentication token with `alg: "none"` to log in as any user linked to a Google account, without knowing their credentials. All deployments with Google authentication enabled are affected. The fix in versions 8.6.3 and 9.1.1-alpha.4 hardcodes the expected `RS256` algorithm instead of trusting the JWT header, and replaces the Google adapter's custom key fetcher with `jwks-rsa` which rejects unknown key IDs. As a workaround, dsable Google authentication until upgrading is possible.

CVSS

Versión: 4.0
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/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: 9.3

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.23%
Percentil entre todas las CVEs puntuadas: 13
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 access95 %
Impacto principalT1078.004 Cloud Accountsstealth · persistence · privilege escalation · initial access90 %

Vulnerabilidad en autenticación Google (JWT sin validación de algoritmo) permite acceso remoto sin credenciales a Parse Server expuesto. CWE-327 (criptografía débil) y token forjado habilitan suplantación de usuarios.

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

Privileged Account Management Active Directory Configuration Vulnerability Scanning User Training User Account Management Password Policies

Tecnologías afectadas (1)

Parseplatform — Parse-server

CWE

CWE-327, CWE-345

Referencias

JSON original (NVD)

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      "value": "Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.3 and 9.1.1-alpha.4, an unauthenticated attacker can forge a Google authentication token with `alg: \"none\"` to log in as any user linked to a Google account, without knowing their credentials. All deployments with Google authentication enabled are affected. The fix in versions 8.6.3 and 9.1.1-alpha.4 hardcodes the expected `RS256` algorithm instead of trusting the JWT header, and replaces the Google adapter's custom key fetcher with `jwks-rsa` which rejects unknown key IDs. As a workaround, dsable Google authentication until upgrading is possible."
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      "value": "Parse Server es un backend de código abierto que puede implementarse en cualquier infraestructura que pueda ejecutar Node.js. Antes de las versiones 8.6.3 y 9.1.1-alpha.4, un atacante no autenticado puede falsificar un token de autenticación de Google con 'alg: \"none\"' para iniciar sesión como cualquier usuario vinculado a una cuenta de Google, sin conocer sus credenciales. Todas las implementaciones con autenticación de Google habilitada se ven afectadas. La corrección en las versiones 8.6.3 y 9.1.1-alpha.4 codifica de forma rígida el algoritmo 'RS256' esperado en lugar de confiar en el encabezado JWT, y reemplaza el recuperador de claves personalizado del adaptador de Google con 'jwks-rsa' que rechaza los ID de clave desconocidos. Como solución alternativa, deshabilite la autenticación de Google hasta que sea posible la actualización."
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