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

Vulnerability from cvelistv5 – Published: 2026-05-28 09:35 – Updated: 2026-06-14 17:57
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
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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 , ≤ * (original_commit_for_fix)
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-06-27T16:20:56+00:00",
      "cve": "CVE-2026-46139",
      "id": "CVE-2026-46139",
      "initial_release_date": "2026-05-28T00:00:00+00:00",
      "product_status:known_affected": "232",
      "product_status:known_not_affected": "42",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: smb: client: use kzalloc to zero-initialize security descriptor buffer",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46139.json",
      "version": "3"
    }
  }
}



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Sightings

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  • 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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