Linux Linux Kernel
CVE-2026-64395
In the Linux kernel, the following vulnerability has been resolved: ksmbd: require source read access for duplicate extents FSCTL_DUPLICATE_EXTENTS_TO_FILE passes the source file directly to vfs_clone_file_range() or vfs_copy_file_range() without checking the SMB access mask granted to the source handle. A handle opened with attribute access can consequently be used to copy file contents into an attacker-readable destination. Require FILE_READ_DATA on the source handle before either VFS operation, matching other ksmbd data-copy paths.
What this means for your business
- It affects Linux Kernel. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.4% chance of attack attempts being seen in the next 30 days, ranking above 34% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Linux Kernel, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Fastnexa security experts
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Scoring
- CVSS
- 7.5 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N- Assigned by
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Dates
- Published
- 2026-07-25
- Last modified
- 2026-09-04
- Sources
- NVD
Affected products
- Linux Linux Kernel5.15 - 6.1.178, 6.2 - 6.6.145, 6.7 - 6.12.96, 6.13 - 6.18.39, 6.19 - 7.1.4
As listed in the NVD configuration data. Not a statement about your estate.
References
- https://git.kernel.org/stable/c/2d2ab6983620c2d60ce7db72133984ca3873b929
- https://git.kernel.org/stable/c/67bdad9cf01b25030e3bf00bbce6c309319d6663
- https://git.kernel.org/stable/c/a10942af27832c2761d020863a46e79bebe0567d
- https://git.kernel.org/stable/c/b0d4d5cb846a1ddb7aaab9adfb5986e4540e6e5f
- https://git.kernel.org/stable/c/cedff600f1642aa982178503552f0d007bc829c8
- https://git.kernel.org/stable/c/db231af842868268839f9f9619c68cb27830d8be