# CVE-2024-26692: smb: Fix regression in writes when non-standard maximum write size negotiated

> Data corruption occurs in Linux kernel SMB writes when non-standard write sizes are negotiated or configured, requiring specific mount parameters or server settings.

- **Severity:** High 8.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 3 Apr 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-26692, DEBIAN-CVE-2024-26692, GHSA-jc4v-c4mw-rmf8, UBUNTU-CVE-2024-26692

## What is CVE-2024-26692?

CVE-2024-26692 is a high-severity vulnerability in Linux kernel, published on 3 Apr 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

smb: Fix regression in writes when non-standard maximum write size negotiated

The conversion to netfs in the 6.3 kernel caused a regression when
maximum write size is set by the server to an unexpected value which is
not a multiple of 4096 (similarly if the user overrides the maximum
write size by setting mount parm "wsize", but sets it to a value that
is not a multiple of 4096).  When negotiated write size is not a
multiple of 4096 the netfs code can skip the end of the final
page when doing large sequential writes, causing data corruption.

This section of code is being rewritten/removed due to a large
netfs change, but until that point (ie for the 6.3 kernel until now)
we can not support non-standard maximum write sizes.

Add a warning if a user specifies a wsize on mount that is not
a multiple of 4096 (and round down), also add a change where we
round down the maximum write size if the server negotiates a value
that is not a multiple of 4096 (we also have to check to make sure that
we do not round it down to zero).

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2024-26692?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-26692?

Apply the vendor's patch.

## Is CVE-2024-26692 being exploited?

There is no known exploitation of CVE-2024-26692 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-26692 and fix it if it is affected.

What it is: CVE-2024-26692 is a high-severity vulnerability in Linux kernel, published on 3 Apr 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2024-26692 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2024-26692/ (Markdown: https://insights.sbomify.com/CVE-2024-26692/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-26692
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-26692
- OSV: https://osv.dev/vulnerability/CVE-2024-26692

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-26692/
Summaries are generated and may contain mistakes; the official description above is the record.