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FKIE_CVE-2026-46139

Vulnerability from fkie_nvd - Published: 2026-05-28 10:16 - Updated: 2026-06-24 17:26
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: use kzalloc to zero-initialize security descriptor buffer Commit 62e7dd0a39c2d ("smb: common: change the data type of num_aces to le16") split struct smb_acl's __le32 num_aces field into __le16 num_aces and __le16 reserved. The reserved field corresponds to Sbz2 in the MS-DTYP ACL wire format, which must be zero [1]. When building an ACL descriptor in build_sec_desc(), we are using a kmalloc()'ed descriptor buffer and writing the fields explicitly using le16() writes now. This never writes to the 2 byte reserved field, leaving it as uninitialized heap data. When the reserved field happens to contain non-zero slab garbage, Samba rejects the security descriptor with "ndr_pull_security_descriptor failed: Range Error", causing chmod to fail with EINVAL. Change kmalloc() to kzalloc() to ensure the entire buffer is zero-initialized. [1] https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/20233ed8-a6c6-4097-aafa-dd545ed24428
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4c3ed344a970aad51388ac3b0145b98318f0e21fPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5e489c6c47a2ac15edbaca153b9348e42c1eacabPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/941a1e6eb35440336913afc88a82103291956d5dPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9bdb2ca31368b7671949dfb94a5d57ffccd01eddPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/be1ef9512a3f5a755895c24f31b334342f4aa15bPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 6.14
linux linux_kernel 6.14
linux linux_kernel 6.14
linux linux_kernel 7.1
linux linux_kernel 7.1
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/cifsacl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4c3ed344a970aad51388ac3b0145b98318f0e21f",
              "status": "affected",
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              "versionType": "git"
            },
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              "status": "affected",
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              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d",
              "versionType": "git"
            },
            {
              "lessThan": "5e489c6c47a2ac15edbaca153b9348e42c1eacab",
              "status": "affected",
              "version": "62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "191f2f444745087c3c51fd6042a0e25f42315ab0",
              "versionType": "git"
            },
            {
              "lessThan": "6.12.88",
              "status": "affected",
              "version": "6.12.23",
              "versionType": "semver"
            },
            {
              "lessThan": "6.14",
              "status": "affected",
              "version": "6.13.11",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/cifsacl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.88",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.30",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
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              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "1FB529E7-FAB4-45C3-84BA-2641F8232248",
              "versionEndExcluding": "6.12.88",
              "versionStartIncluding": "6.12.23",
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            },
            {
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              "vulnerable": true
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              "vulnerable": true
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          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: use kzalloc to zero-initialize security descriptor buffer\n\nCommit 62e7dd0a39c2d (\"smb: common: change the data type of num_aces\nto le16\") split struct smb_acl\u0027s __le32 num_aces field into __le16\nnum_aces and __le16 reserved. The reserved field corresponds to Sbz2\nin the MS-DTYP ACL wire format, which must be zero [1].\n\nWhen building an ACL descriptor in build_sec_desc(), we are using a\nkmalloc()\u0027ed descriptor buffer and writing the fields explicitly using\nle16() writes now. This never writes to the 2 byte reserved field,\nleaving it as uninitialized heap data.\n\nWhen the reserved field happens to contain non-zero slab garbage,\nSamba rejects the security descriptor with \"ndr_pull_security_descriptor\nfailed: Range Error\", causing chmod to fail with EINVAL.\n\nChange kmalloc() to kzalloc() to ensure the entire buffer is\nzero-initialized.\n\n\n[1] https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/20233ed8-a6c6-4097-aafa-dd545ed24428"
    }
  ],
  "id": "CVE-2026-46139",
  "lastModified": "2026-06-24T17:26:46.547",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-05-28T10:16:29.470",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/4c3ed344a970aad51388ac3b0145b98318f0e21f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "url": "https://git.kernel.org/stable/c/5e489c6c47a2ac15edbaca153b9348e42c1eacab"
    },
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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      "url": "https://git.kernel.org/stable/c/be1ef9512a3f5a755895c24f31b334342f4aa15b"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-908"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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