SB20260815308 - Use-after-free in Linux kernel smb server

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Main Vulnerability Database SB20260815308

SB20260815308 - Use-after-free in Linux kernel smb server

Published: August 15, 2026

Security Bulletin ID SB20260815308
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-2026-72422)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 8.7 [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]


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

The vulnerability exists due to a use-after-free in smb3_preauth_hash_rsp() when processing concurrent SMB2 NEGOTIATE requests on the same connection. A remote attacker can send concurrent SMB2 NEGOTIATE requests that trigger a race and dereference freed memory to cause a denial of service.

The issue is a race between the SMB2 NEGOTIATE handler and the response send path, where a NULL check can be bypassed by concurrent freeing of conn->preauth_info before dereference.


Remediation

Install update from vendor's website.

References