SB20260815332 - Use-after-free in Linux kernel bridge



SB20260815332 - Use-after-free in Linux kernel bridge

Published: August 15, 2026

Security Bulletin ID SB20260815332
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Use-after-free (CVE-ID: CVE-2026-72389)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


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

The vulnerability exists due to use-after-free in the STP timer handling in the Linux kernel bridge subsystem when deleting a bridge while the topology change timer is armed on an administratively down bridge. A local user can trigger bridge topology change detection and delete the bridge to cause a denial of service.

The issue occurs because the IFF_UP check was missing in br_topology_change_detection().


Remediation

Install update from vendor's website.