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CVE-2026-42493

Estado: AplazadaAlta (7.5)—

Addressing certain issues, in particular related to operations which may take excessively long and therefore would need preemption, has turned out overly costly. Since alternatives (HVM/PVH: HAP, PV: shim) are commonly available, the decision was to deprecate the functionality, while still retaining it for people to use at their own (security) risk. Memory-wise small enough guests may still be okay to run.

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, PR:N, UI:N indica explotación remota sin privilegios (T1190). CWE-400 (Uncontrolled Resource Consumption) y descripción sobre operaciones excesivamente largas que requieren preemption sugieren denegación de servicio por consumo de recursos en hipervisor Xen.

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

Tecnologías afectadas (1)

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

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-42493",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-42493",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-07-28T15:58:19.075241Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security@xen.org",
      "affectedData": [
        {
          "vendor": "Xen",
          "product": "Xen",
          "versions": [
            {
              "status": "unknown",
              "version": "consult Xen advisory XSA-495"
            }
          ],
          "defaultStatus": "unknown"
        }
      ]
    }
  ],
  "published": "2026-07-28T13:18:32.247",
  "references": [
    {
      "url": "https://xenbits.xenproject.org/xsa/advisory-495.html",
      "source": "security@xen.org"
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2026/07/28/12",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://xenbits.xen.org/xsa/advisory-495.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Addressing certain issues, in particular related to operations which may\ntake excessively long and therefore would need preemption, has turned out\noverly costly.  Since alternatives (HVM/PVH: HAP, PV: shim) are commonly\navailable, the decision was to deprecate the functionality, while still\nretaining it for people to use at their own (security) risk.  Memory-wise\nsmall enough guests may still be okay to run."
    }
  ],
  "lastModified": "2026-07-28T17:16:39.063",
  "sourceIdentifier": "security@xen.org"
}