# CVE-2025-39957: wifi: mac80211: increase scan_ies_len for S1G

> A missing length check for S1G capability elements causes a buffer validation failure, preventing hardware scanning and causing a denial of service in the Linux kernel.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Oct 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-68331, BELL-CVE-2025-39957, DEBIAN-CVE-2025-39957, GHSA-mx4j-wm6m-3mxr, ROOT-OS-DEBIAN-11-CVE-2025-39957, ROOT-OS-DEBIAN-12-CVE-2025-39957, ROOT-OS-DEBIAN-13-CVE-2025-39957, ROOT-OS-UBUNTU-2204-CVE-2025-39957, ROOT-OS-UBUNTU-2404-CVE-2025-39957, UBUNTU-CVE-2025-39957

## What is CVE-2025-39957?

CVE-2025-39957 is a high-severity denial of service vulnerability in Linux kernel, published on 9 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

wifi: mac80211: increase scan_ies_len for S1G

Currently the S1G capability element is not taken into account
for the scan_ies_len, which leads to a buffer length validation
failure in ieee80211_prep_hw_scan() and subsequent WARN in
__ieee80211_start_scan(). This prevents hw scanning from functioning.
To fix ensure we accommodate for the S1G capability length.

## Which versions are affected by CVE-2025-39957?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-39957?

Apply the vendor's patch.

## Is CVE-2025-39957 being exploited?

There is no known exploitation of CVE-2025-39957 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-2025-39957 and fix it if it is affected.

What it is: CVE-2025-39957 is a high-severity denial of service vulnerability in Linux kernel, published on 9 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-39957 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-2025-39957/ (Markdown: https://insights.sbomify.com/CVE-2025-39957/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39957
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39957
- OSV: https://osv.dev/vulnerability/CVE-2025-39957

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39957/
Summaries are generated and may contain mistakes; the official description above is the record.