Vulnerability-Lookup

CVE-2026-64380 (GCVE-0-2026-64380)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-07-25 08:50

Title

smb: client: harden POSIX SID length parsing

Summary

In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.

Severity

No CVSS data available.

Assigner

Linux

References

8 references

URL	Tags
https://git.kernel.org/stable/c/171605aed68380c2f…
https://git.kernel.org/stable/c/4213c120897848302…
https://git.kernel.org/stable/c/96e889bc1e759c83f…
https://git.kernel.org/stable/c/0de5b8e76847f5de2…
https://git.kernel.org/stable/c/427eb7eb46425fec8…
https://git.kernel.org/stable/c/86c5d470f5d42e611…
https://git.kernel.org/stable/c/46a84715a015cb48e…
https://git.kernel.org/stable/c/7ad2bcf2441430bb2…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 349e13ad30b45998bb9937cfe0b32be6f951976d , < 171605aed68380c2fa75dff9b3a1ed427c50065b (git) Affected: 349e13ad30b45998bb9937cfe0b32be6f951976d , < 4213c1208978483021d7d125c131de3985d38f61 (git) Affected: 349e13ad30b45998bb9937cfe0b32be6f951976d , < 96e889bc1e759c83f25093e8c2f3da31b4973f30 (git) Affected: 349e13ad30b45998bb9937cfe0b32be6f951976d , < 0de5b8e76847f5de26f364a82c6602c4881c30da (git) Affected: 349e13ad30b45998bb9937cfe0b32be6f951976d , < 427eb7eb46425fec845a43e861f3d6e2899cae59 (git) Affected: 349e13ad30b45998bb9937cfe0b32be6f951976d , < 86c5d470f5d42e61123b2f4b4f0b91f4eee5b980 (git) Affected: 349e13ad30b45998bb9937cfe0b32be6f951976d , < 46a84715a015cb48e1b9c219dc88c03d8a541ea4 (git) Affected: 349e13ad30b45998bb9937cfe0b32be6f951976d , < 7ad2bcf2441430bb2e918fb3ef9a90d775a6e422 (git)
Linux	Linux	Affected: 5.7 Unaffected: 0 , < 5.7 (semver) Unaffected: 5.10.261 , ≤ 5.10.* (semver) Unaffected: 5.15.212 , ≤ 5.15.* (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.96 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: harden POSIX SID length parsing\n\nposix_info_sid_size() reads sid[1] to obtain the subauthority count,\nbut its existing boundary check still accepts buffers with only one\nremaining byte. Require two bytes before reading sid[1] so all client\npaths that reuse the helper reject truncated POSIX SIDs safely."
        }
      ],
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    "datePublished": "2026-07-25T08:50:30.476Z",
    "dateReserved": "2026-07-19T15:36:31.784Z",
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    "state": "PUBLISHED"
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  }
}

GHSA-86GC-PXPC-4P5H

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31

Details

In the Linux kernel, the following vulnerability has been resolved:

smb: client: harden POSIX SID length parsing

posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-64380"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:21Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: harden POSIX SID length parsing\n\nposix_info_sid_size() reads sid[1] to obtain the subauthority count,\nbut its existing boundary check still accepts buffers with only one\nremaining byte. Require two bytes before reading sid[1] so all client\npaths that reuse the helper reject truncated POSIX SIDs safely.",
  "id": "GHSA-86gc-pxpc-4p5h",
  "modified": "2026-07-25T12:31:33Z",
  "published": "2026-07-25T12:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64380"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-64380 (GCVE-0-2026-64380)

GHSA-86GC-PXPC-4P5H

Tags

Sightings

Nomenclature