# CVE-2026-98208: mmc: sdio_uart: fix xmit_fifo leak when the port table is full

> A memory leak in the Linux kernel SDIO UART driver allows local attackers to exhaust system memory, potentially causing a denial of service.

- **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:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106239, BELL-CVE-2026-98208, DEBIAN-CVE-2026-98208, GHSA-4c3r-52hj-39rr, UBUNTU-CVE-2026-98208

## What is CVE-2026-98208?

CVE-2026-98208 is a memory corruption vulnerability in Linux, published on 6 Oct 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:

mmc: sdio_uart: fix xmit_fifo leak when the port table is full

sdio_uart_add_port() allocates the transmit fifo before claiming a
slot in sdio_uart_table[].  When all UART_NR slots are taken, it
returns -EBUSY with the fifo still allocated, but the probe error
path only kfree()s the port, leaking the transmit fifo.

Free the fifo in the failure path of sdio_uart_add_port() itself so
the function retains nothing on error.

## Which versions are affected by CVE-2026-98208?


## How do I fix CVE-2026-98208?

Apply the vendor's patch.

## Is CVE-2026-98208 being exploited?

There is no known exploitation of CVE-2026-98208 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98208 and fix it if it is affected.

What it is: CVE-2026-98208 is a memory corruption vulnerability in Linux, published on 6 Oct 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-2026-98208 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-2026-98208/ (Markdown: https://insights.sbomify.com/CVE-2026-98208/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98208
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98208
- OSV: https://osv.dev/vulnerability/CVE-2026-98208

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98208/
Summaries are generated and may contain mistakes; the official description above is the record.