CVE-2026-46195 (GCVE-0-2026-46195)
Vulnerability from cvelistv5
Published
2026-05-28 09:36
Modified
2026-06-14 18:01
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building DACL pointers parse_sec_desc(), build_sec_desc(), and the chown path in id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd before proving a DACL header fits inside the returned security descriptor. On 32-bit builds a malicious server can return dacloffset near U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip past the later pointer-based bounds checks. build_sec_desc() and id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped pointer in the chmod/chown rewrite paths. Validate dacloffset numerically before building any DACL pointer and reuse the same helper at the three DACL entry points.
Impacted products
Vendor Product Version
Linux Linux Version: bc3e9dd9d104ca1b75644eab87b38ce8a924aef4
Version: bc3e9dd9d104ca1b75644eab87b38ce8a924aef4
Version: bc3e9dd9d104ca1b75644eab87b38ce8a924aef4
Version: bc3e9dd9d104ca1b75644eab87b38ce8a924aef4
Version: bc3e9dd9d104ca1b75644eab87b38ce8a924aef4
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "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": [
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              "status": "affected",
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            {
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              "versionType": "git"
            }
          ]
        },
        {
          "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": "5.12"
            },
            {
              "lessThan": "5.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.140",
              "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.140",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.88",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.30",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.7",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
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                {
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                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "5.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: validate dacloffset before building DACL pointers\n\nparse_sec_desc(), build_sec_desc(), and the chown path in\nid_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd\nbefore proving a DACL header fits inside the returned security\ndescriptor.\n\nOn 32-bit builds a malicious server can return dacloffset near\nU32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip\npast the later pointer-based bounds checks. build_sec_desc() and\nid_mode_to_cifs_acl() can then dereference DACL fields from the wrapped\npointer in the chmod/chown rewrite paths.\n\nValidate dacloffset numerically before building any DACL pointer and\nreuse the same helper at the three DACL entry points."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-14T18:01:48.626Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ba7f71b6161c0943dafc367565e5843d16b7d505"
        },
        {
          "url": "https://git.kernel.org/stable/c/3b1ddba19e77ee35241cd27f16dc3e8d14e08db7"
        },
        {
          "url": "https://git.kernel.org/stable/c/c688f3ed73d31943334ad2139cb02ec49664322a"
        },
        {
          "url": "https://git.kernel.org/stable/c/8bd07e417b6bda67e317920584e48cb6ee442a8a"
        },
        {
          "url": "https://git.kernel.org/stable/c/f98b48151cc502ada59d9778f0112d21f2586ca3"
        }
      ],
      "title": "smb: client: validate dacloffset before building DACL pointers",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46195",
    "datePublished": "2026-05-28T09:36:48.259Z",
    "dateReserved": "2026-05-13T15:03:33.104Z",
    "dateUpdated": "2026-06-14T18:01:48.626Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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