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CVE-2021-29441

Estado: ModificadaCrítica (9.8)—

Nacos is a platform designed for dynamic service discovery and configuration and service management. In Nacos before version 1.4.1, when configured to use authentication (-Dnacos.core.auth.enabled=true) Nacos uses the AuthFilter servlet filter to enforce authentication. This filter has a backdoor that enables Nacos servers to bypass this filter and therefore skip authentication checks. This mechanism relies on the user-agent HTTP header so it can be easily spoofed. This issue may allow any user to carry out any administrative tasks on the Nacos server.

CVSS

Probabilidad de explotación (EPSS)

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).

Tecnologías afectadas (1)

Alibaba — Nacos

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2021-29441",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 7.5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "PARTIAL"
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        "obtainAllPrivilege": false,
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        "obtainUserPrivilege": false,
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          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
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        "exploitabilityScore": 3.9
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        "cvssData": {
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  "published": "2021-04-27T21:15:07.993",
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  "vulnStatus": "Modified",
  "weaknesses": [
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      "description": [
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          "lang": "en",
          "value": "CWE-290"
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      "description": [
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          "value": "CWE-290"
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  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Nacos is a platform designed for dynamic service discovery and configuration and service management. In Nacos before version 1.4.1, when configured to use authentication (-Dnacos.core.auth.enabled=true) Nacos uses the AuthFilter servlet filter to enforce authentication. This filter has a backdoor that enables Nacos servers to bypass this filter and therefore skip authentication checks. This mechanism relies on the user-agent HTTP header so it can be easily spoofed. This issue may allow any user to carry out any administrative tasks on the Nacos server."
    },
    {
      "lang": "es",
      "value": "Nacos es una plataforma diseñada para el descubrimiento y la configuración dinámica de servicios y la gestión de servicios.&#xa0;En Nacos versiones anteriores a  1.4.1, cuando se configura para usar autenticación (-Dnacos.core.auth.enabled=true), Nacos usa el filtro de servlet AuthFilter para hacer cumplir la autenticación.&#xa0;Este filtro presenta una backdoor que permite a servidores de Nacos omitir este filtro y, por lo tanto, omitir las comprobaciones de autenticación.&#xa0;Este mecanismo es basado en el encabezado HTTP del agente de usuario para que pueda falsificarse fácilmente.&#xa0;Este problema puede permitir a cualquier usuario llevar a cabo cualquier tarea administrativa en el servidor de Nacos"
    }
  ],
  "lastModified": "2026-06-17T03:47:38.877",
  "configurations": [
    {
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        {
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}