# CVE-2026-98685: smb: client: discard post-EOF pagecache when extending a file via clone range

> A local attacker can read stale pagecache data past the end of file when extending files via SMB clone operations in the Linux kernel.

- **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:** AZL-108978, BELL-CVE-2026-98685, DEBIAN-CVE-2026-98685, GHSA-r85p-j355-crhr, UBUNTU-CVE-2026-98685

## What is CVE-2026-98685?

CVE-2026-98685 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:

smb: client: discard post-EOF pagecache when extending a file via clone range

cifs_remap_file_range() discarded the pagecache only for the folios
overlapping the destination region, so when a clone extends the file the
folio straddling the old EOF - which may hold data dirtied past EOF
through an mmap - was never dropped and became visible as file content
once the file was extended.

Start the discard at the smaller of fstart and the old EOF.  i_size is
still old here, so nothing past the old EOF is flushed to the server.

## Which versions are affected by CVE-2026-98685?


## How do I fix CVE-2026-98685?

Apply the vendor's patch.

## Is CVE-2026-98685 being exploited?

There is no known exploitation of CVE-2026-98685 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98685 and fix it if it is affected.

What it is: CVE-2026-98685 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-2026-98685 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-2026-98685/ (Markdown: https://insights.sbomify.com/CVE-2026-98685/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98685
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98685
- OSV: https://osv.dev/vulnerability/CVE-2026-98685

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98685/
Summaries are generated and may contain mistakes; the official description above is the record.