CVE-2026-49143

Estado: AplazadaAlta (8.7)—

BrowserStack Runner through 0.9.5 contains a remote code execution vulnerability in the /_log HTTP handler that allows unauthenticated network-adjacent attackers to execute arbitrary code by submitting crafted JSON request bodies to the handler, which passes user-supplied data to vm.runInNewContext() combined with eval(). Attackers can escape the Node.js vm sandbox by leveraging a host-context Function reference through util.format to access the host process via this.constructor.constructor, achieving full remote code execution on the underlying system without any authentication.

CVSS

Versión: 4.0
Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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: 8.7

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.67%
Percentil entre todas las CVEs puntuadas: 50
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.

ExplotaciónT1210 Exploitation of Remote Serviceslateral movement85 %
Impacto principalT1059 Command and Scripting Interpreterexecution90 %

AV:A (red adyacente) + ejecución arbitraria de código en servidor Node.js sin autenticación via endpoint /_log expuesto.

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 Disable or Remove Feature or Program Vulnerability Scanning Threat Intelligence Program Restrict Web-Based Content Network Segmentation

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Browserstack — Browserstack Runner^AI

CWE

CWE-94

Referencias

JSON original (NVD)

Mostrar

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  "id": "CVE-2026-49143",
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      "sourceIdentifier": "disclosure@vulncheck.com"
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  "metrics": {
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          "options": [
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      }
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    "cvssMetricV40": [
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          "exploitMaturity": "NOT_DEFINED",
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          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
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          "modifiedUserInteraction": "NOT_DEFINED",
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          "modifiedAttackRequirements": "NOT_DEFINED",
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          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
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          "vendor": "browserstack",
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          "versions": [
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              "version": "0",
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  "published": "2026-06-02T21:16:28.070",
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      "source": "disclosure@vulncheck.com"
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          "value": "CWE-94"
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  "descriptions": [
    {
      "lang": "en",
      "value": "BrowserStack Runner through 0.9.5 contains a remote code execution vulnerability in the /_log HTTP handler that allows unauthenticated network-adjacent attackers to execute arbitrary code by submitting crafted JSON request bodies to the handler, which passes user-supplied data to vm.runInNewContext() combined with eval(). Attackers can escape the Node.js vm sandbox by leveraging a host-context Function reference through util.format to access the host process via this.constructor.constructor, achieving full remote code execution on the underlying system without any authentication."
    },
    {
      "lang": "es",
      "value": "BrowserStack Runner hasta la versión 0.9.5 contiene una vulnerabilidad de ejecución remota de código en el gestor HTTP /_log que permite a atacantes adyacentes a la red sin autenticación ejecutar código arbitrario al enviar cuerpos de solicitud JSON manipulados al gestor, el cual pasa datos proporcionados por el usuario a vm.runInNewContext() combinado con eval(). Los atacantes pueden escapar del sandbox vm de Node.js aprovechando una referencia de función de contexto de host a través de util.format para acceder al proceso del host a través de this.constructor.constructor, logrando una ejecución remota de código completa en el sistema subyacente sin autenticación alguna."
    }
  ],
  "lastModified": "2026-07-22T19:10:00.120",
  "sourceIdentifier": "disclosure@vulncheck.com"
}