CVE-2026-63938

Estado: Pendiente de análisisCrítica (9.3)—

In the Linux kernel, the following vulnerability has been resolved:

KVM: SEV: Check PSC request indices against the actual size of the buffer

When processing Page State Change (PSC) requests, validate the PSC buffer against the effective size of the scratch area, which could be less than the maximum size if the guest provided a pointer that isn't exactly at the start of the GHCB shared buffer.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Puntuación base: 9.3

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.20%
Percentil entre todas las CVEs puntuadas: 8
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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto secundarioT1499.004 Application or System Exploitationimpact60 %

Vulnerabilidad de kernel Linux (AV:L) sin interacción de usuario que permite escalada de privilegios mediante validación incorrecta de buffers en KVM/SEV, potenciando ejecución de código y DoS.

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

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

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

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-63938",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 9.3,
          "attackVector": "LOCAL",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 6,
        "exploitabilityScore": 2.5
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "9b54e248d2644be71cb394eb85f31ad99e023a05",
              "lessThan": "5198f70c09a5f6e9e5f5a0a2c6b388f24294b176",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9b54e248d2644be71cb394eb85f31ad99e023a05",
              "lessThan": "75c8d1d7291268b479794fba5808971dc2f5eaf3",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9b54e248d2644be71cb394eb85f31ad99e023a05",
              "lessThan": "505a3b94535583e4265360e2621734e355ef263d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9b54e248d2644be71cb394eb85f31ad99e023a05",
              "lessThan": "121d88de56bc5c0ba0ce2f6381af67f948a7e7c1",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.11",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.93",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver",
              "lessThanOrEqual": "7.0.*"
            },
            {
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-07-19T16:17:12.323",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/121d88de56bc5c0ba0ce2f6381af67f948a7e7c1",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/505a3b94535583e4265360e2621734e355ef263d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5198f70c09a5f6e9e5f5a0a2c6b388f24294b176",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/75c8d1d7291268b479794fba5808971dc2f5eaf3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Check PSC request indices against the actual size of the buffer\n\nWhen processing Page State Change (PSC) requests, validate the PSC buffer\nagainst the effective size of the scratch area, which could be less than\nthe maximum size if the guest provided a pointer that isn't exactly at the\nstart of the GHCB shared buffer."
    }
  ],
  "lastModified": "2026-07-27T17:44:23.777",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}