SB20260727182 - Improper access control in Linux kernel smb server

CSH
CYBERSECURITY HELP
Sign In REGISTER

Main Vulnerability Database SB20260727182

SB20260727182 - Improper access control in Linux kernel smb server

Published: July 27, 2026

Security Bulletin ID SB20260727182
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-2026-64392)

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 filesystem permission checks and delete files or remove ADS xattrs.

The vulnerability exists due to improper access control in ksmbd delete-on-close handling when tearing down deferred or durable handles without request work. A remote user can open a file and trigger delete-on-close processing to bypass filesystem permission checks and delete files or remove ADS xattrs.

The issue occurs because final close operations run with ksmbd worker credentials instead of the credentials captured when the file was opened.


Remediation

Install update from vendor's website.

References