CVE-2026-46139 (GCVE-0-2026-46139)
Vulnerability from cvelistv5
Published
2026-05-28 09:35
Modified
2026-06-14 17:57
Severity ?
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
Impacted products
Vendor Product Version
Linux Linux Version: 1593ddb37bd124c131fe635397df68e854a03108
Version: da087905e3270e2291c0afae39a28e7d183e5ec3
Version: 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d
Version: 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d
Version: 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d
Version: 191f2f444745087c3c51fd6042a0e25f42315ab0
Version: 6.12.23   ≤
Version: 6.13.11   ≤
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{
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          "defaultStatus": "unaffected",
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          "programFiles": [
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      "cpeApplicability": [
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      "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"
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      "providerMetadata": {
        "dateUpdated": "2026-06-14T17:57:22.559Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4c3ed344a970aad51388ac3b0145b98318f0e21f"
        },
        {
          "url": "https://git.kernel.org/stable/c/941a1e6eb35440336913afc88a82103291956d5d"
        },
        {
          "url": "https://git.kernel.org/stable/c/be1ef9512a3f5a755895c24f31b334342f4aa15b"
        },
        {
          "url": "https://git.kernel.org/stable/c/9bdb2ca31368b7671949dfb94a5d57ffccd01edd"
        },
        {
          "url": "https://git.kernel.org/stable/c/5e489c6c47a2ac15edbaca153b9348e42c1eacab"
        }
      ],
      "title": "smb: client: use kzalloc to zero-initialize security descriptor buffer",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46139",
    "datePublished": "2026-05-28T09:35:55.234Z",
    "dateReserved": "2026-05-13T15:03:33.100Z",
    "dateUpdated": "2026-06-14T17:57:22.559Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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