CVE-2026-64399 (GCVE-0-2026-64399)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-08-17 04:54
VLAI
Title
ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE The FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the destination file's data via vfs_clone_file_range() with neither the share-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle fp->daccess check that the other write-bearing arms carry. A client can overwrite destination data on a read-only share, or from a handle opened with only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp). FILE_WRITE_ATTRIBUTES-only destination handle overwrote the file's data via the clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix; require FILE_WRITE_DATA since this writes data.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < bf460ad5958d506492de4524a656439da3f99c51 (git)
Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < 620d133d469295ee7c017ca6aafac335f65c4a5a (git)
Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < 9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6 (git)
Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < baae7b39673ec21073a25e3d14f8feaada01d5df (git)
Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < c917e4522d251071dde9871b9142d8ea1186ebfe (git)
Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < 388e4139db27a9e3612c9d356b826f5b1ff6a9e3 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.15
Unaffected: 0 , < 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 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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        "vulnStatus": "Analyzed",
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            "source": "nvd@nist.gov",
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    "redhat_vex": {
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      "cve": "CVE-2026-64399",
      "id": "CVE-2026-64399",
      "initial_release_date": "2026-07-25T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64399.json",
      "version": "3"
    },
    "suse_vex": {
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      "current_release_date": "2026-09-15T01:49:59Z",
      "cve": "CVE-2026-64399",
      "id": "CVE-2026-64399",
      "initial_release_date": "2026-07-25T16:00:04Z",
      "product_status:known_affected": "125",
      "product_status:known_not_affected": "251",
      "product_status:recommended": "4",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64399",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64399.json",
      "version": "7"
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}



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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.

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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.