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CVE-2026-64264

Estado: AnalizadaMedia (5.5)—

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

fuse-uring: fix EFAULT clobber in fuse_uring_commit

copy_from_user() returns the number of bytes not copied as an unsigned residual on failure (1..sizeof(struct fuse_out_header)). fuse_uring_commit stores that residual in ssize_t err, sets req->out.h.error to -EFAULT, then jumps to out: with err still holding the positive residual.

fuse_uring_req_end() then runs

which overwrites the just-assigned -EFAULT with the positive residual. FUSE callers such as fuse_simple_request() test err < 0 to detect failure, so the positive value is interpreted as success and the caller proceeds with an uninitialised or partial req->out.args.

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Fix by assigning err = -EFAULT in the failure branch before jumping to out, so fuse_uring_req_end() receives a negative errno and sets req->out.h.error to -EFAULT.

Detalles técnicos trazas, registros y código del informe original
    err = copy_from_user(&req->out.h, &ent->headers->in_out,
                         sizeof(req->out.h));
    if (err) {
        req->out.h.error = -EFAULT;
        goto out;          /* err is the positive residual */
    }
    ...
    out:
        fuse_uring_req_end(ent, req, err);

    if (error)
        req->out.h.error = error;

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).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-64264",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "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": "c090c8abae4b6b77a1bee116aa6c385456ebef96",
              "lessThan": "0483fffdeeb363f320e6bf5fc0f0306007507306",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c090c8abae4b6b77a1bee116aa6c385456ebef96",
              "lessThan": "fe604c08d874648a69187f6380e5c7858627dc04",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c090c8abae4b6b77a1bee116aa6c385456ebef96",
              "lessThan": "3a0a8bc51a13951c5141262bf770eeea3e0b6228",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/fuse/dev_uring.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.14",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/fuse/dev_uring.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-07-25T10:17:06.563",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0483fffdeeb363f320e6bf5fc0f0306007507306",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3a0a8bc51a13951c5141262bf770eeea3e0b6228",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/fe604c08d874648a69187f6380e5c7858627dc04",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfuse-uring: fix EFAULT clobber in fuse_uring_commit\n\ncopy_from_user() returns the number of bytes not copied as an unsigned\nresidual on failure (1..sizeof(struct fuse_out_header)). fuse_uring_commit\nstores that residual in ssize_t err, sets req->out.h.error to -EFAULT,\nthen jumps to out: with err still holding the positive residual.\n\n    err = copy_from_user(&req->out.h, &ent->headers->in_out,\n                         sizeof(req->out.h));\n    if (err) {\n        req->out.h.error = -EFAULT;\n        goto out;          /* err is the positive residual */\n    }\n    ...\n    out:\n        fuse_uring_req_end(ent, req, err);\n\nfuse_uring_req_end() then runs\n\n    if (error)\n        req->out.h.error = error;\n\nwhich overwrites the just-assigned -EFAULT with the positive residual.\nFUSE callers such as fuse_simple_request() test err < 0 to detect\nfailure, so the positive value is interpreted as success and the\ncaller proceeds with an uninitialised or partial req->out.args.\n\nFix by assigning err = -EFAULT in the failure branch before jumping\nto out, so fuse_uring_req_end() receives a negative errno and sets\nreq->out.h.error to -EFAULT."
    }
  ],
  "lastModified": "2026-08-17T05:17:25.170",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A14068C8-C11C-44AA-9581-F8861BC66FF8",
              "versionEndExcluding": "6.18.39",
              "versionStartIncluding": "6.14"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6228DDD6-4557-4AA3-9F43-AB995D471E42",
              "versionEndExcluding": "7.1.4",
              "versionStartIncluding": "6.19"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}