CVE-2026-52944

kernel: ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE

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Severity

Unknown

Red Hat Product Security

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CVSS

Review impact separately from score.

Published · June 24, 2026

Updated · June 28, 2026

Description

A flaw was found in the Linux kernel's ksmbd component. This vulnerability allows a client to bypass intended permission restrictions by using the FSCTL_SET_SPARSE operation. Specifically, a client on a read-only share can modify a file's sparse attribute, and clients on writable shares can modify this attribute without the necessary FILE_WRITE_DATA or FILE_WRITE_ATTRIBUTES access. This can lead to unauthorized changes to file properties.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CWE-266 · Incorrect Privilege Assignment