Vulnerability-Lookup

CVE-2026-64392 (GCVE-0-2026-64392)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-07-27 05:00

Title

ksmbd: use opener credentials for delete-on-close

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: use opener credentials for delete-on-close Delete-on-close can be completed by deferred or durable handle teardown, where no request work is available. Both the base-file unlink and the ADS xattr removal consequently run with the ksmbd worker credentials and can bypass filesystem permission checks. Run both operations with the credentials captured in struct file when the handle was opened. This preserves the authenticated user's fsuid, fsgid, supplementary groups and capability restrictions at final close.

Severity

9.1 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Assigner

Linux

References

5 references

URL	Tags
https://git.kernel.org/stable/c/f08b3f451f12eee4a…
https://git.kernel.org/stable/c/18c59109bb6fb816d…
https://git.kernel.org/stable/c/e72c15085b6d86f45…
https://git.kernel.org/stable/c/4b7059974549d278e…
https://git.kernel.org/stable/c/52e2f21911158ec96…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: f44158485826c076335d6860d35872271a83791d , < f08b3f451f12eee4abd8a5981803bc36db84458b (git) Affected: f44158485826c076335d6860d35872271a83791d , < 18c59109bb6fb816d5102171666f87cf1e29901d (git) Affected: f44158485826c076335d6860d35872271a83791d , < e72c15085b6d86f45d224d98aa75b5cace4aaab9 (git) Affected: f44158485826c076335d6860d35872271a83791d , < 4b7059974549d278e30fe70e2a4e421f9839817d (git) Affected: f44158485826c076335d6860d35872271a83791d , < 52e2f21911158ec961cd5aae19c56460db382af0 (git)
Linux	Linux	Affected: 5.15 Unaffected: 0 , < 5.15 (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-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
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        {
          "defaultStatus": "unaffected",
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          "programFiles": [
            "fs/smb/server/vfs.c",
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              "version": "0",
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    "datePublished": "2026-07-25T08:50:38.634Z",
    "dateReserved": "2026-07-19T15:36:31.785Z",
    "dateUpdated": "2026-07-27T05:00:21.820Z",
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      "product_status:under_investigation": "1",
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      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64392.json",
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    "suse_vex": {
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      "status": "interim",
      "title": "SUSE CVE CVE-2026-64392",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64392.json",
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    }
  }
}

GHSA-CQ4Q-MQM3-8R2P

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-27 06:30

Details

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

ksmbd: use opener credentials for delete-on-close

Delete-on-close can be completed by deferred or durable handle teardown, where no request work is available. Both the base-file unlink and the ADS xattr removal consequently run with the ksmbd worker credentials and can bypass filesystem permission checks.

Run both operations with the credentials captured in struct file when the handle was opened. This preserves the authenticated user's fsuid, fsgid, supplementary groups and capability restrictions at final close.

Severity

9.1 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-64392"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:22Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use opener credentials for delete-on-close\n\nDelete-on-close can be completed by deferred or durable handle teardown,\nwhere no request work is available. Both the base-file unlink and the ADS\nxattr removal consequently run with the ksmbd worker credentials and can\nbypass filesystem permission checks.\n\nRun both operations with the credentials captured in struct file when the\nhandle was opened. This preserves the authenticated user\u0027s fsuid, fsgid,\nsupplementary groups and capability restrictions at final close.",
  "id": "GHSA-cq4q-mqm3-8r2p",
  "modified": "2026-07-27T06:30:35Z",
  "published": "2026-07-25T12:31:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64392"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/18c59109bb6fb816d5102171666f87cf1e29901d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4b7059974549d278e30fe70e2a4e421f9839817d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/52e2f21911158ec961cd5aae19c56460db382af0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e72c15085b6d86f45d224d98aa75b5cace4aaab9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f08b3f451f12eee4abd8a5981803bc36db84458b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

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-2026-64392 (GCVE-0-2026-64392)

GHSA-CQ4Q-MQM3-8R2P

Tags

Sightings

Nomenclature