# CVE-2026-89740: serial: imx: serialize imx_uart_ports[] lifetime

> A use-after-free in the Linux kernel i.MX serial driver allows local attackers to execute code or escalate privileges via race conditions during device binding.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-100154, BELL-CVE-2026-89740, DEBIAN-CVE-2026-89740, GHSA-q55c-3wjg-8jjp, UBUNTU-CVE-2026-89740

## What is CVE-2026-89740?

CVE-2026-89740 is an use after free vulnerability in Linux, published on 11 Sep 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:

serial: imx: serialize imx_uart_ports[] lifetime

imx_uart_probe() publishes its devm-allocated port in imx_uart_ports[]
before uart_add_one_port() because console setup uses the table. The entry
is not cleared when adding the port fails or after removal, leaving a
dangling pointer.

A sibling probe can register the shared console through that stale entry.
This was reproduced under KASAN on QEMU mcimx6ul-evk by unbinding a
sibling UART, unbinding the console UART and rebinding the sibling.

Keep the entry valid through uart_remove_one_port(), then clear it. Protect
port addition and removal together with their table updates so sibling
operations cannot interleave. Reject an occupied slot rather than
clobbering an active port during a duplicate-line probe.

## Which versions are affected by CVE-2026-89740?


## How do I fix CVE-2026-89740?

Apply the vendor's patch.

## Is CVE-2026-89740 being exploited?

There is no known exploitation of CVE-2026-89740 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89740 and fix it if it is affected.

What it is: CVE-2026-89740 is an use after free vulnerability in Linux, published on 11 Sep 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-2026-89740 in the wild and no public exploit code.

Affected product: Linux. 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-2026-89740/ (Markdown: https://insights.sbomify.com/CVE-2026-89740/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89740
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89740
- OSV: https://osv.dev/vulnerability/CVE-2026-89740

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89740/
Summaries are generated and may contain mistakes; the official description above is the record.