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 flaw was found in the Linux kernel's ksmbd component. This vulnerability allows an attacker with attribute access to a file to bypass security checks when duplicating file extents. By using the FSCTL_DUPLICATE_EXTENTS_TO_FILE function, an attacker can copy the contents of a source file to a destination that they can read, leading to information disclosure.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64395 https://nvd.nist.gov/vuln/detail/CVE-2026-64395 https://lore.kernel.org/linux-cve-announce/2026072528-CVE-2026-64395-26a3@gregkh/T