# CVE-2026-93198: dm-pcache: validate the persisted dirty_tail chain at load

> A crafted disk image can cause an infinite loop in the Linux kernel dm-pcache writeback worker, leading to 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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-93198, DEBIAN-CVE-2026-93198, GHSA-m9qc-pw52-gvjm, UBUNTU-CVE-2026-93198

## What is CVE-2026-93198?

CVE-2026-93198 is a denial of service vulnerability in Linux, published on 17 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:

dm-pcache: validate the persisted dirty_tail chain at load

The writeback worker follows the persisted dirty_tail chain, which is
decoded from the cache device independently of the key_tail chain that
cache_replay() walks and bounds. A crafted image, whose on-media fields are
authenticated only by a crc32c with a fixed seed, can aim dirty_tail at a
chain of last ksets that never terminates, so cache_writeback_fn() re-arms
itself with no delay forever.

Walk the dirty_tail chain once at load with the same hop cap cache_replay()
uses and fail the table load with -EIO if it does not reach an end within
n_segs hops.

## Which versions are affected by CVE-2026-93198?


## How do I fix CVE-2026-93198?

Apply the vendor's patch.

## Is CVE-2026-93198 being exploited?

There is no known exploitation of CVE-2026-93198 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93198 and fix it if it is affected.

What it is: CVE-2026-93198 is a denial of service vulnerability in Linux, published on 17 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-2026-93198 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-2026-93198/ (Markdown: https://insights.sbomify.com/CVE-2026-93198/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93198
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93198
- OSV: https://osv.dev/vulnerability/CVE-2026-93198

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93198/
Summaries are generated and may contain mistakes; the official description above is the record.