SB20260727166 - Use-after-free in Linux kernel smb server

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Main Vulnerability Database SB20260727166

SB20260727166 - Use-after-free in Linux kernel smb server

Published: July 27, 2026

Security Bulletin ID SB20260727166
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Use-after-free (CVE-ID: CVE-2026-64397)

CWE-ID: CWE-416 - Use After Free

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


The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to a use-after-free in smb2_query_dir() and the ksmbd directory enumeration state when handling concurrent QUERY_DIRECTORY requests using the same file handle. A remote user can send concurrent QUERY_DIRECTORY requests on the same file handle to cause a denial of service.

The issue occurs because a pointer to stack-allocated private data is stored in shared readdir state and can be overwritten while an iterate_dir() callback is still using it.


Remediation

Install update from vendor's website.

References