ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64399
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-25 10:17:23 UTC
Updated2026-07-27 05:16:47 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.004910000 probability, percentile 0.393660000 (date 2026-07-27)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected eb817368f50c1cbe1bd07044124aad7db6330e3a bf460ad5958d506492de4524a656439da3f99c51 git Not specified
CNA Linux Linux affected eb817368f50c1cbe1bd07044124aad7db6330e3a 620d133d469295ee7c017ca6aafac335f65c4a5a git Not specified
CNA Linux Linux affected eb817368f50c1cbe1bd07044124aad7db6330e3a 9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6 git Not specified
CNA Linux Linux affected eb817368f50c1cbe1bd07044124aad7db6330e3a baae7b39673ec21073a25e3d14f8feaada01d5df git Not specified
CNA Linux Linux affected eb817368f50c1cbe1bd07044124aad7db6330e3a c917e4522d251071dde9871b9142d8ea1186ebfe git Not specified
CNA Linux Linux affected eb817368f50c1cbe1bd07044124aad7db6330e3a 388e4139db27a9e3612c9d356b826f5b1ff6a9e3 git Not specified
CNA Linux Linux affected 5.15 Not specified
CNA Linux Linux unaffected 5.15 semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.96 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.39 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.4 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfe 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5df 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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