# CVE-2026-93811: ksmbd: Fix acl.sd_buf memory leak and invalid sd_size error handling

> A memory leak and improper error handling in the Linux kernel ksmbd module can lead to resource exhaustion and denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Sep 2026
- **Updated:** 3 Oct 2026
- **Also known as:** AZL-104000, BELL-CVE-2026-93811, DEBIAN-CVE-2026-93811, GHSA-47cf-52hv-jjq9, UBUNTU-CVE-2026-93811

## What is CVE-2026-93811?

CVE-2026-93811 is a memory corruption vulnerability in Linux, published on 24 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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

ksmbd: Fix acl.sd_buf memory leak and invalid sd_size error handling

1. When ndr_decode_v4_ntacl() fails, the code jumped to free_n_data
   which only freed n.data, skipping kfree(acl.sd_buf) and leaking
   the buffer. Zero-initialize struct xattr_ntacl acl, reorder error
   labels to out_free to release acl.sd_buf on all error paths.

2. if (acl.sd_size < sizeof(struct smb_ntsd)) is true, original code
   returned success without freeing sd_buf and left stale *pntsd.
   Set rc = -EINVAL before jumping to out_free to return error code and
   free buffer.

## Which versions are affected by CVE-2026-93811?


## How do I fix CVE-2026-93811?

Apply the vendor's patch.

## Is CVE-2026-93811 being exploited?

There is no known exploitation of CVE-2026-93811 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93811 and fix it if it is affected.

What it is: CVE-2026-93811 is a memory corruption vulnerability in Linux, published on 24 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-93811 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-2026-93811/ (Markdown: https://insights.sbomify.com/CVE-2026-93811/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93811
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93811
- OSV: https://osv.dev/vulnerability/CVE-2026-93811

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93811/
Summaries are generated and may contain mistakes; the official description above is the record.