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CVE-2026-72382

Estado: RecibidaAlta (8.8)—

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

ksmbd: reject undersized DACLs before parsing ACEs

parse_dacl() limits the attacker-controlled ACE count by comparing it with the number of minimal ACEs that fit in the DACL size. The DACL size field is 16 bits, but the expression subtracts sizeof(struct smb_acl). Because sizeof() is unsigned, a DACL size smaller than the ACL header underflows to a large size_t.

A malicious client can reach this with:

Thus a malformed security descriptor can make num_aces pass the guard and drive large temporary ACL state and pointer-array allocations.

Leer descripción completaMostrar menos

Reject DACLs smaller than struct smb_acl before doing the subtraction, so the ACE count check cannot be bypassed by the underflow.

Detalles técnicos trazas, registros y código del informe original
SMB2_SET_INFO (InfoType=SMB2_O_INFO_SECURITY)
  -> smb2_set_info_sec()
  -> set_info_sec()
  -> parse_sec_desc()
  -> parse_dacl()
     -> init_acl_state(..., 0xffff)
     -> init_acl_state(..., 0xffff)
     -> kmalloc_objs(..., 0xffff)

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.

Vulnerabilidad de desbordamiento de enteros en ksmbd (SMB del kernel Linux) explotable por cliente autenticado (PR:L, red). El subdesbordamiento permite bypass de validación y asignaciones excesivas de memoria (DoS) o posible escalada de privilegios en el kernel.

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 ProgramApplication Isolation and SandboxingExploit ProtectionUpdate SoftwareVulnerability ScanningPrivileged Account Management

Tecnologías afectadas (1)

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

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-72382",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.8,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "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": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "16fb65ec15fe7c90f50a2115854bfd9a032d4023",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "282847c0cf22f2e961155ac8e42f6eeab7e16049",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "d020e7f27bf65eecd3805404702f716b2b6d9e73",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "15a9e9b8f7f5d7f380ae54c6f5bcbc0bdcb0f3cd",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "60908f7ebcd9b6cde74ad5711fab0f49c7970949",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/smb/server/smbacl.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.15",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/smb/server/smbacl.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T06:22:11.707",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/15a9e9b8f7f5d7f380ae54c6f5bcbc0bdcb0f3cd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/16fb65ec15fe7c90f50a2115854bfd9a032d4023",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/282847c0cf22f2e961155ac8e42f6eeab7e16049",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/60908f7ebcd9b6cde74ad5711fab0f49c7970949",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d020e7f27bf65eecd3805404702f716b2b6d9e73",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: reject undersized DACLs before parsing ACEs\n\nparse_dacl() limits the attacker-controlled ACE count by comparing it\nwith the number of minimal ACEs that fit in the DACL size. The DACL size\nfield is 16 bits, but the expression subtracts sizeof(struct smb_acl).\nBecause sizeof() is unsigned, a DACL size smaller than the ACL header\nunderflows to a large size_t.\n\nA malicious client can reach this with:\n\nSMB2_SET_INFO (InfoType=SMB2_O_INFO_SECURITY)\n  -> smb2_set_info_sec()\n  -> set_info_sec()\n  -> parse_sec_desc()\n  -> parse_dacl()\n     -> init_acl_state(..., 0xffff)\n     -> init_acl_state(..., 0xffff)\n     -> kmalloc_objs(..., 0xffff)\n\nThus a malformed security descriptor can make num_aces pass the guard\nand drive large temporary ACL state and pointer-array allocations.\n\nReject DACLs smaller than struct smb_acl before doing the subtraction,\nso the ACE count check cannot be bypassed by the underflow."
    }
  ],
  "lastModified": "2026-08-17T06:18:42.640",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}