# CVE-2026-98587: firewire: cdev: fix back-transition for iso_resource_auto client resource

> A race condition in the Linux kernel firewire driver allows local attackers to cause a state transition error, potentially leading to a denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **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-2026-98587, GHSA-7hq7-xmgm-jjr4, UBUNTU-CVE-2026-98587

## What is CVE-2026-98587?

CVE-2026-98587 is a 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:

firewire: cdev: fix back-transition for iso_resource_auto client resource

The todo member of iso_resource_auto structure represents the state of the
client resource and normally transitions in the following order:

    ISO_RES_AUTO_ALLOC -> ISO_RES_AUTO_REALLOC -> ISO_RES_AUTO_DEALLOC

However, concurrent access from the work item and the file descriptor
release function can cause the state to transition backwards from
ISO_RES_AUTO_DEALLOC to ISO_RES_AUTO_REALLOC.

Prevent the back-transition by checking the current state before
updating it in the work item.

## Which versions are affected by CVE-2026-98587?


## How do I fix CVE-2026-98587?

Apply the vendor's patch.

## Is CVE-2026-98587 being exploited?

There is no known exploitation of CVE-2026-98587 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98587 and fix it if it is affected.

What it is: CVE-2026-98587 is a 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-2026-98587 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-2026-98587/ (Markdown: https://insights.sbomify.com/CVE-2026-98587/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98587
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98587
- OSV: https://osv.dev/vulnerability/CVE-2026-98587

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98587/
Summaries are generated and may contain mistakes; the official description above is the record.