# CVE-2023-54250: ksmbd: avoid out of bounds access in decode_preauth_ctxt()

> An out-of-bounds access in the Linux kernel's ksmbd module allows attackers to cause denial of service or potentially execute code via crafted SMB requests.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Dec 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-54250, DEBIAN-CVE-2023-54250, GHSA-f39w-x49r-j8p2, UBUNTU-CVE-2023-54250

## What is CVE-2023-54250?

CVE-2023-54250 is a high-severity memory corruption vulnerability in Linux, published on 30 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

ksmbd: avoid out of bounds access in decode_preauth_ctxt()

Confirm that the accessed pneg_ctxt->HashAlgorithms address sits within
the SMB request boundary; deassemble_neg_contexts() only checks that the
eight byte smb2_neg_context header + (client controlled) DataLength are
within the packet boundary, which is insufficient.

Checking for sizeof(struct smb2_preauth_neg_context) is overkill given
that the type currently assumes SMB311_SALT_SIZE bytes of trailing Salt.

## Which versions are affected by CVE-2023-54250?


## How do I fix CVE-2023-54250?

Apply the vendor's patch.

## Is CVE-2023-54250 being exploited?

There is no known exploitation of CVE-2023-54250 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-54250 and fix it if it is affected.

What it is: CVE-2023-54250 is a high-severity memory corruption vulnerability in Linux, published on 30 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-54250 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-2023-54250/ (Markdown: https://insights.sbomify.com/CVE-2023-54250/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-54250
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-54250
- OSV: https://osv.dev/vulnerability/CVE-2023-54250

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-54250/
Summaries are generated and may contain mistakes; the official description above is the record.