# CVE-2026-53337: net: bonding: fix NULL pointer dereference in bond_do_ioctl()

> A local attacker with CAP_NET_ADMIN can cause a kernel crash by triggering a NULL pointer dereference in the bonding driver via ioctl calls.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 1 Jul 2026
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2026-53337, DEBIAN-CVE-2026-53337, GHSA-73rm-r64m-jh58, ROOT-OS-UBUNTU-2204-CVE-2026-53337, ROOT-OS-UBUNTU-2404-CVE-2026-53337, UBUNTU-CVE-2026-53337

## What is CVE-2026-53337?

CVE-2026-53337 is a medium-severity vulnerability in Linux kernel, published on 1 Jul 2026. 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: bonding: fix NULL pointer dereference in bond_do_ioctl()

In bond_do_ioctl(), slave_dev is obtained via __dev_get_by_name() which
can return NULL if the requested interface name does not exist. However,
the subsequent slave_dbg() call is placed before the NULL check:

    slave_dev = __dev_get_by_name(net, ifr->ifr_slave);
    slave_dbg(bond_dev, slave_dev, "slave_dev=%p:\n", slave_dev); //here
    if (!slave_dev)
        return -ENODEV;

The slave_dbg() macro expands to netdev_dbg(bond_dev, "(slave %s): " fmt,
(slave_dev)->name, ...) which unconditionally dereferences slave_dev->name
before the NULL check is performed. This results in a NULL pointer
dereference kernel oops when a user calls bonding ioctl (e.g.
SIOCBONDENSLAVE, SIOCBONDRELEASE, etc.) with a non-existent slave
interface name.

This is reachable from userspace via the bonding ioctl interface with
CAP_NET_ADMIN capability, making it a potential local denial-of-service
vector.

Fix by moving the slave_dbg() call after the NULL check.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-53337?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53337?

Apply the vendor's patch.

## Is CVE-2026-53337 being exploited?

There is no known exploitation of CVE-2026-53337 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-2026-53337 and fix it if it is affected.

What it is: CVE-2026-53337 is a medium-severity vulnerability in Linux kernel, published on 1 Jul 2026. 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-2026-53337 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-2026-53337/ (Markdown: https://insights.sbomify.com/CVE-2026-53337/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53337
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53337
- OSV: https://osv.dev/vulnerability/CVE-2026-53337

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53337/
Summaries are generated and may contain mistakes; the official description above is the record.