# CVE-2024-35839: netfilter: bridge: replace physindev with physinif in nf_bridge_info

> A use-after-free or null dereference in the Linux kernel netfilter bridge module can cause a system crash when processing ARP queues.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 May 2024
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-67737, BELL-CVE-2024-35839, DEBIAN-CVE-2024-35839, GHSA-gw6v-2949-7c2m, ROOT-OS-DEBIAN-11-CVE-2024-35839, ROOT-OS-UBUNTU-2204-CVE-2024-35839, UBUNTU-CVE-2024-35839

## What is CVE-2024-35839?

CVE-2024-35839 is a high-severity vulnerability in Linux kernel, published on 17 May 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:

netfilter: bridge: replace physindev with physinif in nf_bridge_info

An skb can be added to a neigh->arp_queue while waiting for an arp
reply. Where original skb's skb->dev can be different to neigh's
neigh->dev. For instance in case of bridging dnated skb from one veth to
another, the skb would be added to a neigh->arp_queue of the bridge.

As skb->dev can be reset back to nf_bridge->physindev and used, and as
there is no explicit mechanism that prevents this physindev from been
freed under us (for instance neigh_flush_dev doesn't cleanup skbs from
different device's neigh queue) we can crash on e.g. this stack:

arp_process
  neigh_update
    skb = __skb_dequeue(&neigh->arp_queue)
      neigh_resolve_output(..., skb)
        ...
          br_nf_dev_xmit
            br_nf_pre_routing_finish_bridge_slow
              skb->dev = nf_bridge->physindev
              br_handle_frame_finish

Let's use plain ifindex instead of net_device link. To peek into the
original net_device we will use dev_get_by_index_rcu(). Thus either we
get device and are safe to use it or we don't get it and drop skb.

## Which versions are affected by CVE-2024-35839?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-35839?

Apply the vendor's patch.

## Is CVE-2024-35839 being exploited?

There is no known exploitation of CVE-2024-35839 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-35839 and fix it if it is affected.

What it is: CVE-2024-35839 is a high-severity vulnerability in Linux kernel, published on 17 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-35839 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-35839/ (Markdown: https://insights.sbomify.com/CVE-2024-35839/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-35839
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-35839
- OSV: https://osv.dev/vulnerability/CVE-2024-35839

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-35839/
Summaries are generated and may contain mistakes; the official description above is the record.