CVE-2026-64399

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.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3	Patch
https://git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5a	Patch
https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6	Patch
https://git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5df	Patch
https://git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51	Patch
https://git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfe	Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::

History

No history.

Information

Published : 2026-07-25 10:17

Updated : 2026-09-04 14:46

NVD link : CVE-2026-64399

Mitre link : CVE-2026-64399

CVE.ORG link : CVE-2026-64399

JSON object : View

Products Affected

linux

linux_kernel

CWE

NVD-CWE-noinfo

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