SB20260727183 - Improper access control in Linux kernel smb server

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Main Vulnerability Database SB20260727183

SB20260727183 - Improper access control in Linux kernel smb server

Published: July 27, 2026

Security Bulletin ID SB20260727183
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-2026-64393)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]


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

The vulnerability exists due to improper access control in SMB2 SET_INFO handlers when processing SET_INFO requests. A remote user can send a specially crafted SET_INFO request to bypass intended permission checks.

The issue arises because path-based VFS helpers perform permission and LSM checks using worker credentials instead of the credentials captured when the file handle was opened.


Remediation

Install update from vendor's website.

References