CVE-2026-64399

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxeb817368f50c1cbe1bd07044124aad7db6330e3a < bf460ad5958d506492de4524a656439da3f99c51affected
LinuxLinuxeb817368f50c1cbe1bd07044124aad7db6330e3a < 620d133d469295ee7c017ca6aafac335f65c4a5aaffected
LinuxLinuxeb817368f50c1cbe1bd07044124aad7db6330e3a < 9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6affected
LinuxLinuxeb817368f50c1cbe1bd07044124aad7db6330e3a < baae7b39673ec21073a25e3d14f8feaada01d5dfaffected
LinuxLinuxeb817368f50c1cbe1bd07044124aad7db6330e3a < c917e4522d251071dde9871b9142d8ea1186ebfeaffected
LinuxLinuxeb817368f50c1cbe1bd07044124aad7db6330e3a < 388e4139db27a9e3612c9d356b826f5b1ff6a9e3affected
LinuxLinux5.15affected
LinuxLinux0 < 5.15unaffected
LinuxLinux6.1.178 <= 6.1.*unaffected
LinuxLinux6.6.145 <= 6.6.*unaffected
LinuxLinux6.12.96 <= 6.12.*unaffected
LinuxLinux6.18.39 <= 6.18.*unaffected
LinuxLinux7.1.4 <= 7.1.*unaffected
LinuxLinux7.2-rc1 <= *unaffected

Weaknesses

References