FKIE_CVE-2026-20074

Vulnerability from fkie_nvd - Published: 2026-03-11 17:16 - Updated: 2026-03-12 21:08
Severity ?
7.4 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Summary
A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly. This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and a denial of service (DoS) condition. Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and must have formed an adjacency.  
References
psirt@cisco.comhttps://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-dos-kDMxpSzK
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly.\r\n\r\nThis vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and a denial of service (DoS) condition.\r\nNote: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and must have formed an adjacency.\u0026nbsp;\u0026nbsp;"
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad en la funci\u00f3n de enrutamiento multi-instancia de Intermediate System-to-Intermediate System (IS-IS) de Cisco IOS XR Software podr\u00eda permitir a un atacante no autenticado y adyacente causar que el proceso IS-IS se reinicie inesperadamente.\n\nEsta vulnerabilidad se debe a una validaci\u00f3n de entrada insuficiente de los paquetes IS-IS de entrada. Un atacante podr\u00eda explotar esta vulnerabilidad enviando paquetes IS-IS manipulados a un dispositivo afectado despu\u00e9s de formar una adyacencia. Un exploit exitoso podr\u00eda permitir al atacante causar que el proceso IS-IS se reinicie inesperadamente, lo que resultar\u00eda en una p\u00e9rdida temporal de conectividad a las redes anunciadas y una condici\u00f3n de denegaci\u00f3n de servicio (DoS).\nNota: El protocolo IS-IS es un protocolo de enrutamiento. Para explotar esta vulnerabilidad, un atacante debe ser adyacente en Capa 2 al dispositivo afectado y debe haber formado una adyacencia."
    }
  ],
  "id": "CVE-2026-20074",
  "lastModified": "2026-03-12T21:08:22.643",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.4,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 4.0,
        "source": "psirt@cisco.com",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-03-11T17:16:55.470",
  "references": [
    {
      "source": "psirt@cisco.com",
      "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-dos-kDMxpSzK"
    }
  ],
  "sourceIdentifier": "psirt@cisco.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-1287"
        }
      ],
      "source": "psirt@cisco.com",
      "type": "Primary"
    }
  ]
}


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