SB20260816243 - Use-after-free in Linux kernel bridge

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Main Vulnerability Database SB20260816243

SB20260816243 - Use-after-free in Linux kernel bridge

Published: August 16, 2026

Security Bulletin ID SB20260816243
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-2026-74480)

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 a use-after-free in br_multicast_leave_group() in the bridge multicast handling code when processing fast-leave operations on port groups. A local user can trigger deletion of a matching port group to cause a denial of service.

The issue can occur when multicast-to-unicast had been enabled, allowing multiple port groups for the same port and group with different source MAC addresses, and is later disabled so entries are matched by port only.


Remediation

Install update from vendor's website.

References