# CVE-2026-98267: 9p: Fix v9fs_issue_write() to update i_size and remote_i_size

> A flaw in the Linux kernel 9p filesystem allows attackers to read stale file size data, potentially disclosing information about file contents.

- **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:** BELL-CVE-2026-98267, DEBIAN-CVE-2026-98267, GHSA-87v5-rjqw-6p7m, UBUNTU-CVE-2026-98267

## What is CVE-2026-98267?

CVE-2026-98267 is a 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:

9p: Fix v9fs_issue_write() to update i_size and remote_i_size

Fix v9fs_issue_write() to update i_size and remote_i_size to the new size
of the server file if we made it larger, using the start fpos and the count
returned by p9_client_write() to calculate the new minimum file size.

This assumes that if the 9P server makes a short write (say it hits
ENOSPC), a reduced count is returned.

## Which versions are affected by CVE-2026-98267?


## How do I fix CVE-2026-98267?

Apply the vendor's patch.

## Is CVE-2026-98267 being exploited?

There is no known exploitation of CVE-2026-98267 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98267 and fix it if it is affected.

What it is: CVE-2026-98267 is a 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-2026-98267 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-2026-98267/ (Markdown: https://insights.sbomify.com/CVE-2026-98267/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98267
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98267
- OSV: https://osv.dev/vulnerability/CVE-2026-98267

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98267/
Summaries are generated and may contain mistakes; the official description above is the record.