Vulnerability-Lookup

GHSA-V762-VR2V-9263

Vulnerability from github – Published: 2026-06-24 12:30 – Updated: 2026-06-24 12:30

Details

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

ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE

FSCTL_SET_SPARSE in fsctl_set_sparse() modifies the file's sparse attribute and saves it through xattr without any permission checks.

This exposes two issues:

1) A client on a read-only share can change the sparse attribute on files it opened, even though the share is read-only. Other FSCTL write operations already check test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE), but FSCTL_SET_SPARSE does not.

2) Even on writable shares, clients without FILE_WRITE_DATA or FILE_WRITE_ATTRIBUTES access should not modify the sparse attribute. Similar handle-level checks exist in other functions but are missing here.

Add both share-level writable check and per-handle access check. Use goto out on error to avoid leaking file references.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-52944"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T10:17:19Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE\n\nFSCTL_SET_SPARSE in fsctl_set_sparse() modifies the file\u0027s sparse\nattribute and saves it through xattr without any permission checks.\n\nThis exposes two issues:\n\n1) A client on a read-only share can change the sparse attribute\n   on files it opened, even though the share is read-only.\n   Other FSCTL write operations already check\n   test_tree_conn_flag(work-\u003etcon, KSMBD_TREE_CONN_FLAG_WRITABLE),\n   but FSCTL_SET_SPARSE does not.\n\n2) Even on writable shares, clients without FILE_WRITE_DATA or\n   FILE_WRITE_ATTRIBUTES access should not modify the sparse\n   attribute. Similar handle-level checks exist in other functions\n   but are missing here.\n\nAdd both share-level writable check and per-handle access check.\nUse goto out on error to avoid leaking file references.",
  "id": "GHSA-v762-vr2v-9263",
  "modified": "2026-06-24T12:30:31Z",
  "published": "2026-06-24T12:30:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52944"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3127a884525dc8ca4def73254bfcd3ccef0bf812"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aef151bcfa494bfe983669de2726734b534adb73"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cc57232cae23c0df91b4a59d0f519141ce9b5b02"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/de9eb0b44fa9123170e6245b49638e0e453c10f8"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-52944 (GCVE-0-2026-52944)

Vulnerability from cvelistv5 – Published: 2026-06-24 09:59 – Updated: 2026-06-24 09:59

Title

ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE FSCTL_SET_SPARSE in fsctl_set_sparse() modifies the file's sparse attribute and saves it through xattr without any permission checks. This exposes two issues: 1) A client on a read-only share can change the sparse attribute on files it opened, even though the share is read-only. Other FSCTL write operations already check test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE), but FSCTL_SET_SPARSE does not. 2) Even on writable shares, clients without FILE_WRITE_DATA or FILE_WRITE_ATTRIBUTES access should not modify the sparse attribute. Similar handle-level checks exist in other functions but are missing here. Add both share-level writable check and per-handle access check. Use goto out on error to avoid leaking file references.

Severity

No CVSS data available.

Assigner

Linux

References

4 references

URL	Tags
https://git.kernel.org/stable/c/3127a884525dc8ca4…
https://git.kernel.org/stable/c/de9eb0b44fa912317…
https://git.kernel.org/stable/c/aef151bcfa494bfe9…
https://git.kernel.org/stable/c/cc57232cae23c0df9…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 3127a884525dc8ca4def73254bfcd3ccef0bf812 (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < de9eb0b44fa9123170e6245b49638e0e453c10f8 (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < aef151bcfa494bfe983669de2726734b534adb73 (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < cc57232cae23c0df91b4a59d0f519141ce9b5b02 (git)
Linux	Linux	Affected: 5.15 Unaffected: 0 , < 5.15 (semver) Unaffected: 6.6.143 , ≤ 6.6.* (semver) Unaffected: 6.18.35 , ≤ 6.18.* (semver) Unaffected: 7.0.12 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3127a884525dc8ca4def73254bfcd3ccef0bf812",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "de9eb0b44fa9123170e6245b49638e0e453c10f8",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "aef151bcfa494bfe983669de2726734b534adb73",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "cc57232cae23c0df91b4a59d0f519141ce9b5b02",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.12",
              "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": "6.6.143",
                  "versionStartIncluding": "5.15",
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                },
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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        }
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        "dateUpdated": "2026-06-24T09:59:09.149Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/cc57232cae23c0df91b4a59d0f519141ce9b5b02"
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      ],
      "title": "ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-52944",
    "datePublished": "2026-06-24T09:59:09.149Z",
    "dateReserved": "2026-06-09T07:44:35.371Z",
    "dateUpdated": "2026-06-24T09:59:09.149Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Action not permitted

GHSA-V762-VR2V-9263

CVE-2026-52944 (GCVE-0-2026-52944)

Tags

Sightings

Nomenclature