FKIE_CVE-2026-64380

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-07-27 05:16
Severity
8.2 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "171605aed68380c2fa75dff9b3a1ed427c50065b",
              "status": "affected",
              "version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
              "versionType": "git"
            },
            {
              "lessThan": "4213c1208978483021d7d125c131de3985d38f61",
              "status": "affected",
              "version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
              "versionType": "git"
            },
            {
              "lessThan": "96e889bc1e759c83f25093e8c2f3da31b4973f30",
              "status": "affected",
              "version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
              "versionType": "git"
            },
            {
              "lessThan": "0de5b8e76847f5de26f364a82c6602c4881c30da",
              "status": "affected",
              "version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
              "versionType": "git"
            },
            {
              "lessThan": "427eb7eb46425fec845a43e861f3d6e2899cae59",
              "status": "affected",
              "version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
              "versionType": "git"
            },
            {
              "lessThan": "86c5d470f5d42e61123b2f4b4f0b91f4eee5b980",
              "status": "affected",
              "version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
              "versionType": "git"
            },
            {
              "lessThan": "46a84715a015cb48e1b9c219dc88c03d8a541ea4",
              "status": "affected",
              "version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
              "versionType": "git"
            },
            {
              "lessThan": "7ad2bcf2441430bb2e918fb3ef9a90d775a6e422",
              "status": "affected",
              "version": "349e13ad30b45998bb9937cfe0b32be6f951976d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.7"
            },
            {
              "lessThan": "5.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: harden POSIX SID length parsing\n\nposix_info_sid_size() reads sid[1] to obtain the subauthority count,\nbut its existing boundary check still accepts buffers with only one\nremaining byte. Require two bytes before reading sid[1] so all client\npaths that reuse the helper reject truncated POSIX SIDs safely."
    }
  ],
  "id": "CVE-2026-64380",
  "lastModified": "2026-07-27T05:16:44.690",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.2,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 4.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-25T10:17:21.220",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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