CVE-2026-64399 Affecting linux-6.12 package, versions <6.12.100-1~deb12u1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-ECHOLATEST-LINUX612-18579245
- published7 Aug 2026
- disclosed25 Jul 2026
Introduced: 25 Jul 2026
CVE-2026-64399 (opens in a new tab)How to fix?
Upgrade Echo:latest linux-6.12 to version 6.12.100-1~deb12u1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Echo.
See How to fix? for Echo:latest relevant fixed versions and status.
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.
References
- https://advisory.echohq.com/cve/CVE-2026-64399
- https://git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3
- https://git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5a
- https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6
- https://git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5df
- https://git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51
- https://git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfe