# CVE-2025-38657: wifi: rtw89: mcc: prevent shift wrapping in rtw89_core_mlsr_switch()

> A shift wrapping vulnerability in the rtw89 WiFi driver allows root users to trigger potential out-of-bounds access via debugfs.

- **Severity:** High 7.3 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/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:** 22 Aug 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-38657, GHSA-pxq5-v3xq-vvp3, UBUNTU-CVE-2025-38657

## What is CVE-2025-38657?

CVE-2025-38657 is a high-severity vulnerability in Linux kernel, published on 22 Aug 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: rtw89: mcc: prevent shift wrapping in rtw89_core_mlsr_switch()

The "link_id" value comes from the user via debugfs.  If it's larger
than BITS_PER_LONG then that would result in shift wrapping and
potentially an out of bounds access later.  In fact, we can limit it
to IEEE80211_MLD_MAX_NUM_LINKS (15).

Fortunately, only root can write to debugfs files so the security
impact is minimal.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2025-38657?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-38657?

Apply the vendor's patch.

## Is CVE-2025-38657 being exploited?

There is no known exploitation of CVE-2025-38657 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-2025-38657 and fix it if it is affected.

What it is: CVE-2025-38657 is a high-severity vulnerability in Linux kernel, published on 22 Aug 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-2025-38657 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-2025-38657/ (Markdown: https://insights.sbomify.com/CVE-2025-38657/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38657
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38657
- OSV: https://osv.dev/vulnerability/CVE-2025-38657

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38657/
Summaries are generated and may contain mistakes; the official description above is the record.