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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.49%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.49% probability · 41th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3Patch
- https://git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5aPatch
- https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6Patch
- https://git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5dfPatch
- https://git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51Patch
- https://git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfePatch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.