# CVE-2026-99035: mmc: mtk-sd: Cancel request timeout work on remove


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 23 Oct 2026
- **Updated:** 23 Oct 2026
- **Also known as:** AZL-110900, BELL-CVE-2026-99035, DEBIAN-CVE-2026-99035, GHSA-pwxj-3q2q-r972, UBUNTU-CVE-2026-99035

## What is CVE-2026-99035?

CVE-2026-99035 is a vulnerability in Linux, published on 23 Oct 2026. 

### Official description

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

mmc: mtk-sd: Cancel request timeout work on remove

The driver queues req_timeout while a request is active.
msdc_request_done() uses cancel_delayed_work(), which does not wait for
a timeout callback that has already started.

The timeout callback calls mmc_request_done(), which wakes the request
waiter, and then continues to use host->dev_comp and check the SDIO IRQ.
During unbind, msdc_drv_remove() can return and the managed mmc_host can
be freed before the callback finishes.

KASAN reported use-after-free accesses in msdc_request_done() and
msdc_recheck_sdio_irq() in each of three unbind tests.  The same tests
completed without a kernel diagnostic after this change.

Call cancel_delayed_work_sync() after mmc_remove_host() has stopped new
requests and before the driver releases the host resources.

## Which versions are affected by CVE-2026-99035?


## How do I fix CVE-2026-99035?

Upgrade to a fixed version.

## Is CVE-2026-99035 being exploited?

There is no known exploitation of CVE-2026-99035 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99035 and fix it if it is affected.

What it is: CVE-2026-99035 is a vulnerability in Linux, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99035 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-2026-99035/ (Markdown: https://insights.sbomify.com/CVE-2026-99035/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99035
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99035
- OSV: https://osv.dev/vulnerability/CVE-2026-99035

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99035/
Summaries are generated and may contain mistakes; the official description above is the record.