CVE-2024-40920 net: bridge: mst: fix suspicious rcu usage in br_mst_set_state

What is CVE-2024-40920?

CVE-2024-40920 is a high-severity use after free vulnerability in Linux kernel, published on 12 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

net: bridge: mst: fix suspicious rcu usage in br_mst_set_state

I converted br_mst_set_state to RCU to avoid a vlan use-after-free but forgot to change the vlan group dereference helper. Switch to vlan group RCU deref helper to fix the suspicious rcu usage warning.

Weakness: CWE-416

Which versions are affected by CVE-2024-40920?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-40920?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2024-40920 being exploited?

There is no known exploitation of CVE-2024-40920 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2024-40920, DEBIAN-CVE-2024-40920, GHSA-5c2v-7jgp-gfhr, UBUNTU-CVE-2024-40920.