# CVE-2026-46195: smb: client: validate dacloffset before building DACL pointers

> A malicious SMB server can trigger an integer overflow in the Linux kernel SMB client, leading to potential code execution or denial of service via crafted security descriptors.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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:** 28 May 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-89013, BELL-CVE-2026-46195, DEBIAN-CVE-2026-46195, GHSA-rp7m-xq2f-r4cg, ROOT-OS-DEBIAN-12-CVE-2026-46195, ROOT-OS-UBUNTU-2204-CVE-2026-46195, ROOT-OS-UBUNTU-2404-CVE-2026-46195, UBUNTU-CVE-2026-46195

## What is CVE-2026-46195?

CVE-2026-46195 is a critical vulnerability in Linux kernel, published on 28 May 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:

smb: client: validate dacloffset before building DACL pointers

parse_sec_desc(), build_sec_desc(), and the chown path in
id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd
before proving a DACL header fits inside the returned security
descriptor.

On 32-bit builds a malicious server can return dacloffset near
U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip
past the later pointer-based bounds checks. build_sec_desc() and
id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped
pointer in the chmod/chown rewrite paths.

Validate dacloffset numerically before building any DACL pointer and
reuse the same helper at the three DACL entry points.

Weakness: CWE-787 (Out-of-bounds Write), CWE-476 (NULL Pointer Dereference), CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-46195?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46195?

Apply the vendor's patch.

## Is CVE-2026-46195 being exploited?

There is no known exploitation of CVE-2026-46195 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-2026-46195 and fix it if it is affected.

What it is: CVE-2026-46195 is a critical vulnerability in Linux kernel, published on 28 May 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-2026-46195 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-2026-46195/ (Markdown: https://insights.sbomify.com/CVE-2026-46195/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46195
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46195
- OSV: https://osv.dev/vulnerability/CVE-2026-46195

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46195/
Summaries are generated and may contain mistakes; the official description above is the record.