CVE-2026-46139 (GCVE-0-2026-46139)

Vulnerability from cvelistv5 – Published: 2026-05-28 09:35 – Updated: 2026-05-28 09:35
VLAI
Title
smb: client: use kzalloc to zero-initialize security descriptor buffer
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
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1593ddb37bd124c131fe635397df68e854a03108 , < 4c3ed344a970aad51388ac3b0145b98318f0e21f (git)
Affected: da087905e3270e2291c0afae39a28e7d183e5ec3 , < 941a1e6eb35440336913afc88a82103291956d5d (git)
Affected: 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d , < be1ef9512a3f5a755895c24f31b334342f4aa15b (git)
Affected: 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d , < 9bdb2ca31368b7671949dfb94a5d57ffccd01edd (git)
Affected: 62e7dd0a39c2d0d7ff03274c36df971f1b3d2d0d , < 5e489c6c47a2ac15edbaca153b9348e42c1eacab (git)
Affected: 191f2f444745087c3c51fd6042a0e25f42315ab0 (git)
Affected: 6.12.23 , < 6.12.88 (semver)
Affected: 6.13.11 , < 6.14 (semver)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.12.88 , ≤ 6.12.* (semver)
Unaffected: 6.18.30 , ≤ 6.18.* (semver)
Unaffected: 7.0.7 , ≤ 7.0.* (semver)
Unaffected: 7.1-rc3 , ≤ * (original_commit_for_fix)
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          "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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        {
          "url": "https://git.kernel.org/stable/c/9bdb2ca31368b7671949dfb94a5d57ffccd01edd"
        },
        {
          "url": "https://git.kernel.org/stable/c/5e489c6c47a2ac15edbaca153b9348e42c1eacab"
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    "dateReserved": "2026-05-13T15:03:33.100Z",
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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