# CVE-2025-9558: Bluetooth: Mesh: Out-of-Bound Write in gen_prov_start

> An out-of-bounds write in Zephyr's Bluetooth Mesh provisioning allows attackers to corrupt memory, potentially leading to code execution or crashes.

- **Severity:** High 7.6 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Nov 2025
- **Updated:** 13 Oct 2026
- **Also known as:** GHSA-8wvr-688x-68vr

## What is CVE-2025-9558?

CVE-2025-9558 is a high-severity memory corruption vulnerability in zephyrproject-rtos Zephyr, published on 26 Nov 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

There is a potential OOB Write vulnerability in the gen_prov_start function in pb_adv.c. The full length of the received data is copied into the link.rx.buf receiver buffer without any validation on the data size.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2025-9558?


## How do I fix CVE-2025-9558?

No fix has been published for CVE-2025-9558 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-9558 being exploited?

There is no known exploitation of CVE-2025-9558 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-9558 and fix it if it is affected.

What it is: CVE-2025-9558 is a high-severity memory corruption vulnerability in zephyrproject-rtos Zephyr, published on 26 Nov 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-2025-9558 in the wild and no public exploit code.

Affected product: zephyrproject-rtos Zephyr. 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-2025-9558/ (Markdown: https://insights.sbomify.com/CVE-2025-9558/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-9558
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-9558
- OSV: https://osv.dev/vulnerability/CVE-2025-9558

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-9558/
Summaries are generated and may contain mistakes; the official description above is the record.