# CVE-2026-98478: scsi: ufs: core: Keep internal commands dispatchable during error handling

> A deadlock in the Linux kernel UFS driver during error handling causes a denial of service by preventing internal command dispatch.

- **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:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-98478, GHSA-56m6-r6q3-6xw7, UBUNTU-CVE-2026-98478

## What is CVE-2026-98478?

CVE-2026-98478 is a denial of service vulnerability in Linux, published on 18 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:

scsi: ufs: core: Keep internal commands dispatchable during error handling

Commit 08b12cda6c44 ("scsi: ufs: core: Switch to scsi_get_internal_cmd()")
switched UFS internal commands to allocate requests on
hba->host->pseudo_sdev->request_queue, which shares the host tagset with
regular LUNs.

During error recovery, ufshcd_err_handling_prepare() calls
blk_mq_quiesce_tagset(&hba->host->tag_set), marking all queues in the
tagset as quiesced, including pseudo_sdev->request_queue. When
ufshcd_verify_dev_init() subsequently issues internal commands (e.g. NOP
OUT UPIU) via blk_execute_rq(), blk_mq_run_hw_queue() skips running the
quiesced queue, resulting in an unrecoverable circular wait deadlock.

Keep quiescing the tagset and unquiesce the pseudo SCSI device on top of
that, so internal commands stay dispatchable while the logical units remain
quiesced. Re-quiesce the pseudo device before unquiescing the tagset so
that quiesce_depth stays balanced.

Clock scaling and ufshcd_pause_command_processing() are unaffected: they
keep quiescing the whole tagset, internal commands included.

## Which versions are affected by CVE-2026-98478?


## How do I fix CVE-2026-98478?

Apply the vendor's patch.

## Is CVE-2026-98478 being exploited?

There is no known exploitation of CVE-2026-98478 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98478 and fix it if it is affected.

What it is: CVE-2026-98478 is a denial of service vulnerability in Linux, published on 18 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-2026-98478 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-2026-98478/ (Markdown: https://insights.sbomify.com/CVE-2026-98478/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98478
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98478
- OSV: https://osv.dev/vulnerability/CVE-2026-98478

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98478/
Summaries are generated and may contain mistakes; the official description above is the record.