Use-after-free in Linux kernel - CVE-2026-74480

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Main Vulnerability Database Vulnerabilities #VU143307

Use-after-free in Linux kernel - CVE-2026-74480

Published: August 16, 2026


Vulnerability identifier: #VU143307
CSH Severity: Low
CVSS v4: 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]
CVE-ID: CVE-2026-74480
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

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.


Affected software

Linux kernel
Debian Linux
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat CodeReady Linux Builder for x86_64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for ARM 64
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support
Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support
Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support
Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support
Ubuntu
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
kernel (Red Hat package)
kernel-rt (Red Hat package)
linux-nvidia-tegra (Ubuntu package)
linux (Debian package)

How to mitigate CVE-2026-74480

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel (Red Hat package) - addressed in versions 3.10.0-1160.160.1.el7, 4.18.0-305.204.1.el8_4, 4.18.0-372.211.1.el8_6, 4.18.0-477.164.1.el8_8, 4.18.0-553.160.1.el8_10, 5.14.0-284.190.1.el9_2, 5.14.0-427.148.1.el9_4, 5.14.0-570.138.1.el9_6, 6.12.0-55.102.1.el10_0, 6.12.0-231.19.el10nv, 6.12.0-259.26.el10nv
kernel-rt (Red Hat package) - addressed in versions 3.10.0-1160.160.1.rt56.1312.el7, 4.18.0-553.160.1.rt7.501.el8_10, 5.14.0-284.190.1.rt14.475.el9_2
linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1035.38
linux (Debian package) - update to 6.12.105-1

External References

Related Security Bulletins