# CVE-2025-22039: ksmbd: fix overflow in dacloffset bounds check

> An integer overflow in the Linux kernel's ksmbd module allows bypassing bounds checks, leading to out-of-bounds memory access and kernel crashes.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 16 Apr 2025
- **Updated:** 14 Sep 2026
- **Also known as:** BELL-CVE-2025-22039, DEBIAN-CVE-2025-22039, GHSA-xm3p-r4jv-jxcf, ROOT-OS-DEBIAN-12-CVE-2025-22039, ROOT-OS-UBUNTU-2204-CVE-2025-22039, ROOT-OS-UBUNTU-2404-CVE-2025-22039, UBUNTU-CVE-2025-22039

## What is CVE-2025-22039?

CVE-2025-22039 is a high-severity vulnerability in Linux kernel, published on 16 Apr 2025. 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 overflow in dacloffset bounds check

The dacloffset field was originally typed as int and used in an
unchecked addition, which could overflow and bypass the existing
bounds check in both smb_check_perm_dacl() and smb_inherit_dacl().

This could result in out-of-bounds memory access and a kernel crash
when dereferencing the DACL pointer.

This patch converts dacloffset to unsigned int and uses
check_add_overflow() to validate access to the DACL.

Weakness: CWE-190 (Integer Overflow or Wraparound), CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2025-22039?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-22039?

Apply the vendor's patch.

## Is CVE-2025-22039 being exploited?

There is no known exploitation of CVE-2025-22039 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-2025-22039 and fix it if it is affected.

What it is: CVE-2025-22039 is a high-severity vulnerability in Linux kernel, published on 16 Apr 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-22039 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-2025-22039/ (Markdown: https://insights.sbomify.com/CVE-2025-22039/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-22039
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-22039
- OSV: https://osv.dev/vulnerability/CVE-2025-22039

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-22039/
Summaries are generated and may contain mistakes; the official description above is the record.