Linux Kernel Vulnerability in ksmbd File System Management

CVE-2026-52944

What is CVE-2026-52944?

A vulnerability exists in the Linux Kernel's ksmbd file system management that allows unauthorized modification of a file's sparse attribute through FSCTL_SET_SPARSE. This occurs in two main scenarios: first, clients on read-only shares could alter files they accessed, which should not be permitted. Additionally, clients lacking the necessary access rights can still modify the sparse attribute on writable shares. This oversight stems from an absence of proper permission checks, which has now been addressed by implementing necessary share-level and handle-level checks, ensuring more robust security.

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