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CVE-2025-20271

Estado: AplazadaAlta (8.6)—

A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition in the Cisco AnyConnect service on an affected device.

This vulnerability is due to variable initialization errors when an SSL VPN session is established. An attacker could exploit this vulnerability by sending a sequence of crafted HTTPS requests to an affected device.

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A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to restart, resulting in the failure of all established SSL VPN sessions and forcing remote users to initiate a new VPN connection and re-authenticate. A sustained attack could prevent new SSL VPN connections from being established, effectively making the Cisco AnyConnect VPN service unavailable for all legitimate users.

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vector CVSS AV:N/AC:L/PR:N sin interacción permite explotación remota de aplicación expuesta (T1190). El ataque causa reinicio del servicio VPN y fallo de sesiones, manifestándose como negación de servicio contra la aplicación (T1499.004).

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

Filter Network TrafficVulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkApplication Isolation and Sandboxing

Tecnologías afectadas (3)

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

Cisco — Anyconnect VPN ServerAICisco — Meraki MXAICisco — Meraki Z Series Teleworker GatewayAI

CWE

Referencias

JSON original (NVD)

Mostrar
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  "id": "CVE-2025-20271",
  "cveTags": [],
  "metrics": {
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-20271",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
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            {
              "automatable": "yes"
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            {
              "technicalImpact": "partial"
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          "version": "2.0.3",
          "timestamp": "2025-06-18T17:56:26.880823Z"
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    "cvssMetricV31": [
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        "type": "Secondary",
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          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
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  "affected": [
    {
      "source": "psirt@cisco.com",
      "affectedData": [
        {
          "vendor": "Cisco",
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          "versions": [
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              "status": "affected",
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  "published": "2025-06-18T17:15:29.053",
  "references": [
    {
      "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-meraki-mx-vpn-dos-sM5GCfm7",
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      "lang": "en",
      "value": "A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition in the Cisco AnyConnect service on an affected device.\r\n\r\nThis vulnerability is due to variable initialization errors when an SSL VPN session is established. An attacker could exploit this vulnerability by sending a sequence of crafted HTTPS requests to an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to restart, resulting in the failure of all established SSL VPN sessions and forcing remote users to initiate a new VPN connection and re-authenticate. A sustained attack could prevent new SSL VPN connections from being established, effectively making the Cisco AnyConnect VPN service unavailable for all legitimate users."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad en el servidor VPN Cisco AnyConnect de los dispositivos Cisco Meraki MX y Cisco Meraki Z Series Teleworker Gateway podría permitir que un atacante remoto no autenticado provoque una denegación de servicio (DoS) en el servicio Cisco AnyConnect de un dispositivo afectado. Esta vulnerabilidad se debe a errores de inicialización variables al establecer una sesión VPN SSL. Un atacante podría explotar esta vulnerabilidad enviando una secuencia de solicitudes HTTPS manipuladas a un dispositivo afectado. Una explotación exitosa podría permitir al atacante reiniciar el servidor VPN Cisco AnyConnect, lo que provocaría el fallo de todas las sesiones VPN SSL establecidas y obligaría a los usuarios remotos a iniciar una nueva conexión VPN y a autenticarse de nuevo. Un ataque continuo podría impedir el establecimiento de nuevas conexiones VPN SSL, lo que haría que el servicio VPN Cisco AnyConnect no estuviera disponible para todos los usuarios legítimos."
    }
  ],
  "lastModified": "2026-06-17T08:41:14.283",
  "sourceIdentifier": "psirt@cisco.com"
}