# CVE-2026-53400: i2c: core: fix adapter registration race

> A race condition in the Linux kernel i2c core allows attackers to trigger NULL-pointer dereferences or use-after-free errors, causing system crashes.

- **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:** 19 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-92564, BELL-CVE-2026-53400, DEBIAN-CVE-2026-53400, GHSA-9p96-44q4-p2j5, ROOT-OS-DEBIAN-11-CVE-2026-53400, ROOT-OS-DEBIAN-12-CVE-2026-53400, ROOT-OS-UBUNTU-2204-CVE-2026-53400, UBUNTU-CVE-2026-53400

## What is CVE-2026-53400?

CVE-2026-53400 is a high-severity vulnerability in Linux kernel, published on 19 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:

i2c: core: fix adapter registration race

Adapters can be looked up based on their id using i2c_get_adapter()
which takes a reference to the embedded struct device.

Make sure that the adapter (including its struct device) has been
initialised before adding it to the IDR to avoid accessing uninitialised
data which could, for example, lead to NULL-pointer dereferences or
use-after-free.

Note that the i2c-dev chardev, which is registered from a bus notifier,
currently uses i2c_get_adapter() so the adapter needs to be added to the
IDR before registration.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-53400?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53400?

Apply the vendor's patch.

## Is CVE-2026-53400 being exploited?

There is no known exploitation of CVE-2026-53400 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-2026-53400 and fix it if it is affected.

What it is: CVE-2026-53400 is a high-severity vulnerability in Linux kernel, published on 19 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-2026-53400 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-2026-53400/ (Markdown: https://insights.sbomify.com/CVE-2026-53400/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53400
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53400
- OSV: https://osv.dev/vulnerability/CVE-2026-53400

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53400/
Summaries are generated and may contain mistakes; the official description above is the record.