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CVE-2026-53395

Estado: AnalizadaAlta (7.5)—

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

nfsd: fix dead ACL conflict guard in nfsd4_create

nfsd4_create() steals create->cr_dpacl/cr_pacl into the local nfsd_attrs via the designated initializer, then immediately sets the source pointers to NULL. The subsequent conflict guard tests the already-nilled source fields, making it permanently dead code:

When a client encodes both FATTR4_WORD0_ACL and FATTR4_WORD2_POSIX_{DEFAULT,ACCESS}_ACL in the same CREATE fattr bitmap, nfsd4_acl_to_attr() overwrites attrs.na_pacl/na_dpacl without releasing the originals, leaking two posix_acl slab objects per request. Repeated requests cause unbounded slab exhaustion.

Leer descripción completaMostrar menos

Fix by checking attrs.na_dpacl/na_pacl (the stolen values) instead of the nilled create->cr_dpacl/cr_pacl, matching the correct pattern already used in nfsd4_setattr().

Detalles técnicos trazas, registros y código del informe original
    if (create->cr_acl) {
        if (create->cr_dpacl || create->cr_pacl)  /* always false */

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 remota en nfsd (NFS daemon) sin autenticación ni interacción: vector CVSS AV:N/PR:N/UI:N. CWE-674 (uso incorrecto de API) causa fuga de memoria en objetos ACL, permitiendo DoS por agotamiento de slab. El atacante explota nfsd4_create() enviando peticiones CREATE con atributos ACL conf

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 ScanningRestrict File and Directory PermissionsPrivileged Account ManagementRemote Data StorageNetwork Segmentation

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-53395",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "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": "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": "d2ca50606f5f0235d7780c1cd73b6614a5d07620",
              "lessThan": "8371cc5c0a2cc2a71b3dcfd47ff1f7fcfc526a5e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d2ca50606f5f0235d7780c1cd73b6614a5d07620",
              "lessThan": "a60f25a800846ab8e5a13f8a9d05111f2aee55a7",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/nfsd/nfs4proc.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "7.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/nfsd/nfs4proc.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-07-19T12:16:50.597",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/8371cc5c0a2cc2a71b3dcfd47ff1f7fcfc526a5e",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a60f25a800846ab8e5a13f8a9d05111f2aee55a7",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-674"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix dead ACL conflict guard in nfsd4_create\n\nnfsd4_create() steals create->cr_dpacl/cr_pacl into the local\nnfsd_attrs via the designated initializer, then immediately sets the\nsource pointers to NULL. The subsequent conflict guard tests the\nalready-nilled source fields, making it permanently dead code:\n\n    if (create->cr_acl) {\n        if (create->cr_dpacl || create->cr_pacl)  /* always false */\n\nWhen a client encodes both FATTR4_WORD0_ACL and\nFATTR4_WORD2_POSIX_{DEFAULT,ACCESS}_ACL in the same CREATE fattr\nbitmap, nfsd4_acl_to_attr() overwrites attrs.na_pacl/na_dpacl without\nreleasing the originals, leaking two posix_acl slab objects per\nrequest. Repeated requests cause unbounded slab exhaustion.\n\nFix by checking attrs.na_dpacl/na_pacl (the stolen values) instead of\nthe nilled create->cr_dpacl/cr_pacl, matching the correct pattern\nalready used in nfsd4_setattr()."
    }
  ],
  "lastModified": "2026-08-17T05:17:14.033",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "63CFDFF9-82B8-4490-8239-D88ABC42DF23",
              "versionEndExcluding": "7.1.3",
              "versionStartIncluding": "7.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}