SB2026062642 - NULL pointer dereference in Linux kernel smb server

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Main Vulnerability Database SB2026062642

SB2026062642 - NULL pointer dereference in Linux kernel smb server

Published: June 26, 2026

Security Bulletin ID SB2026062642
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) NULL pointer dereference (CVE-ID: CVE-2026-53271)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


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

The vulnerability exists due to a null pointer dereference in smb2_oplock_break_noti() and smb2_lease_break_noti() in fs/smb/server/oplock.c when handling oplock or lease break notifications during a concurrent SMB2 LOGOFF. A remote attacker can trigger a concurrent logoff condition to cause a denial of service.

The issue is remotely triggerable and results in a kernel oops when ksmbd_conn_r_count_inc(conn) dereferences a NULL connection pointer.


Remediation

Install update from vendor's website.

References