SB20260720197 - Use-after-free in Linux kernel bridge

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Main Vulnerability Database SB20260720197

SB20260720197 - Use-after-free in Linux kernel bridge

Published: July 20, 2026

Security Bulletin ID SB20260720197
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-2026-64032)

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 bridge multicast handling in net/bridge/br_multicast.c when removing a bridge port after toggling multicast snooping states. A local user can trigger bridge port state transitions that leave a multicast context enabled on a freed bridge port to cause a denial of service.

The issue occurs when per-VLAN multicast snooping is enabled and global multicast snooping is toggled in a way that leaves both per-port and per-{port, VLAN} multicast contexts enabled on the same port.


Remediation

Install update from vendor's website.

References