SB2026081726 - Improper access control in Linux kernel smb server

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Main Vulnerability Database SB2026081726

SB2026081726 - Improper access control in Linux kernel smb server

Published: August 17, 2026

Security Bulletin ID SB2026081726
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper access control (CVE-ID: CVE-2026-68457)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to bypass intended file permission checks.

The vulnerability exists due to improper access control in ksmbd FSCTL mutation handlers when processing SET_SPARSE, SET_ZERO_DATA, or SET_COMPRESSION operations on an open SMB handle. A remote user can invoke these operations so they are performed with ksmbd worker credentials to bypass intended file permission checks.

The issue arises because helper calls may independently revalidate inode permissions, ownership, or LSM policy instead of relying solely on the SMB handle access mask.


Remediation

Install update from vendor's website.

References