# CVE-2026-64393: ksmbd: run set info with opener credentials

> Attackers can escalate privileges by exploiting credential mishandling in the ksmbd SMB server when setting file information.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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:** 25 Jul 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-64393, DEBIAN-CVE-2026-64393, GHSA-r5f9-v87x-9739, ROOT-OS-DEBIAN-12-CVE-2026-64393, ROOT-OS-UBUNTU-2204-CVE-2026-64393, UBUNTU-CVE-2026-64393

## What is CVE-2026-64393?

CVE-2026-64393 is a critical vulnerability in Linux kernel, published on 25 Jul 2026. 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: run set info with opener credentials

SMB2 SET_INFO handlers call path-based VFS helpers after checking the
access mask granted to the SMB handle. Those helpers perform their owner,
inode permission and LSM checks using the current ksmbd worker credentials.

Run the complete SET_INFO dispatch with the credentials captured when the
handle was opened. This also removes the separate security information
credential setup and keeps all SET_INFO classes under one credential scope.

Direct override_creds() is used because it can nest with the request
credential overrides already used by rename and link helpers.

## Which versions are affected by CVE-2026-64393?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64393?

Apply the vendor's patch.

## Is CVE-2026-64393 being exploited?

There is no known exploitation of CVE-2026-64393 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-2026-64393 and fix it if it is affected.

What it is: CVE-2026-64393 is a critical vulnerability in Linux kernel, published on 25 Jul 2026. 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-2026-64393 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-2026-64393/ (Markdown: https://insights.sbomify.com/CVE-2026-64393/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64393
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64393
- OSV: https://osv.dev/vulnerability/CVE-2026-64393

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64393/
Summaries are generated and may contain mistakes; the official description above is the record.