In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE
FSCTL_SET_SPARSE in fsctl_set_sparse() modifies the file's sparse
attribute and saves it through xattr without any permission checks.
This exposes two issues:
1) A client on a read-only share can change the sparse attribute
on files it opened, even though the share is read-only.
Other FSCTL write operations already check
test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE),
but FSCTL_SET_SPARSE does not.
2) Even on writable shares, clients without FILE_WRITE_DATA or
FILE_WRITE_ATTRIBUTES access should not modify the sparse
attribute. Similar handle-level checks exist in other functions
but are missing here.
Add both share-level writable check and per-handle access check.
Use goto out on error to avoid leaking file references.
References
Configurations
Configuration 1 (hide)
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History
No history.
Information
Published : 2026-06-24 10:17
Updated : 2026-09-14 12:17
NVD link : CVE-2026-52944
Mitre link : CVE-2026-52944
CVE.ORG link : CVE-2026-52944
JSON object : View
Products Affected
linux
- linux_kernel
CWE
