CVE-2026-64395 Details
Description
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.
A vulnerability in the Linux kernel's ksmbd component allows for improper access control when duplicating file extents. The issue arises because the FSCTL_DUPLICATE_EXTENTS_TO_FILE command passes the source file directly to VFS file cloning functions without verifying the SMB access rights of the source handle. This oversight can be exploited by using a handle with attribute access to transfer file contents to a destination that is readable by the attacker. The vulnerability affects the Linux kernel stable tree.
The vulnerability has been addressed by requiring FILE_READ_DATA access on the source handle before performing the duplication operation. Users should upgrade to the latest version of the Linux kernel where this fix has been applied.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/2d2ab6983620c2d60ce7db72133984ca3873b929 | kernel.org | Patch |
| https://git.kernel.org/stable/c/67bdad9cf01b25030e3bf00bbce6c309319d6663 | kernel.org | Patch |
| https://git.kernel.org/stable/c/a10942af27832c2761d020863a46e79bebe0567d | kernel.org | Patch |
| https://git.kernel.org/stable/c/b0d4d5cb846a1ddb7aaab9adfb5986e4540e6e5f | kernel.org | Patch |
| https://git.kernel.org/stable/c/cedff600f1642aa982178503552f0d007bc829c8 | kernel.org | Patch |
| https://git.kernel.org/stable/c/db231af842868268839f9f9619c68cb27830d8be | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-noinfo | Insufficient Information to Classify Weakness | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 5.15, < 6.1.178 >= 6.2, < 6.6.145 >= 6.7, < 6.12.96 >= 6.13, < 6.18.39 >= 6.19, < 7.1.4 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 4, 2026 | Initial Analysis | [email protected] |
| Aug 17, 2026 | CVE Modified | kernel.org |
| Jul 27, 2026 | CVE Modified | kernel.org |
| Jul 25, 2026 | New CVE Received | kernel.org |