# CVE-2026-98883: serial: 8250_port: recognize UPIO_AU


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 23 Oct 2026
- **Updated:** 26 Oct 2026
- **Also known as:** AZL-110564, BELL-CVE-2026-98883, DEBIAN-CVE-2026-98883, GHSA-g9xp-whrx-5gjh, UBUNTU-CVE-2026-98883

## What is CVE-2026-98883?

CVE-2026-98883 is a vulnerability in Linux, published on 23 Oct 2026. 

### Official description

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

serial: 8250_port: recognize UPIO_AU

My MIPS Alchemy systems generate the following warning during
probe of the 8250 driver:

WARNING: drivers/tty/serial/8250/8250_port.c:462 at set_io_from_upio+0xfc/0x124, CPU#0: swapper/0/1
Unsupported UART type 4
[...]
[<80521d40>] set_io_from_upio+0xfc/0x124
[<80521dfc>] serial8250_set_defaults+0x94/0xe0
[<80520fb4>] serial8250_register_8250_port+0x288/0x51c
[<805214ec>] serial8250_probe+0x160/0x1e8
[<8053b5f0>] platform_probe+0x64/0x90

The least invasive fix is to recognize UPIO_AU (type 4) in set_io_from_upio()
and do nothing, since all parameters have already been set up in
8250_rt288x.c::au_platform_setup().

Run-tested on Alchemy Au1300 platform.

## Which versions are affected by CVE-2026-98883?


## How do I fix CVE-2026-98883?

Upgrade to a fixed version.

## Is CVE-2026-98883 being exploited?

There is no known exploitation of CVE-2026-98883 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98883 and fix it if it is affected.

What it is: CVE-2026-98883 is a vulnerability in Linux, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-98883 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-2026-98883/ (Markdown: https://insights.sbomify.com/CVE-2026-98883/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98883
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98883
- OSV: https://osv.dev/vulnerability/CVE-2026-98883

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98883/
Summaries are generated and may contain mistakes; the official description above is the record.