# CVE-2025-39937: net: rfkill: gpio: Fix crash due to dereferencering uninitialized pointer

> An attacker with local access to specific hardware can cause a kernel crash by triggering a null pointer dereference in the rfkill GPIO driver.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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:** 4 Oct 2025
- **Updated:** 11 May 2026
- **Also known as:** AZL-68150, AZL-75333, BELL-CVE-2025-39937, DEBIAN-CVE-2025-39937, GHSA-cg67-c42g-wcjm, ROOT-OS-DEBIAN-11-CVE-2025-39937, ROOT-OS-DEBIAN-12-CVE-2025-39937, ROOT-OS-DEBIAN-13-CVE-2025-39937, ROOT-OS-UBUNTU-2204-CVE-2025-39937, ROOT-OS-UBUNTU-2404-CVE-2025-39937, UBUNTU-CVE-2025-39937

## What is CVE-2025-39937?

CVE-2025-39937 is a medium-severity vulnerability in Linux kernel, published on 4 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:

net: rfkill: gpio: Fix crash due to dereferencering uninitialized pointer

Since commit 7d5e9737efda ("net: rfkill: gpio: get the name and type from
device property") rfkill_find_type() gets called with the possibly
uninitialized "const char *type_name;" local variable.

On x86 systems when rfkill-gpio binds to a "BCM4752" or "LNV4752"
acpi_device, the rfkill->type is set based on the ACPI acpi_device_id:

        rfkill->type = (unsigned)id->driver_data;

and there is no "type" property so device_property_read_string() will fail
and leave type_name uninitialized, leading to a potential crash.

rfkill_find_type() does accept a NULL pointer, fix the potential crash
by initializing type_name to NULL.

Note likely sofar this has not been caught because:

1. Not many x86 machines actually have a "BCM4752"/"LNV4752" acpi_device
2. The stack happened to contain NULL where type_name is stored

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2025-39937?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-39937?

Apply the vendor's patch.

## Is CVE-2025-39937 being exploited?

There is no known exploitation of CVE-2025-39937 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-2025-39937 and fix it if it is affected.

What it is: CVE-2025-39937 is a medium-severity vulnerability in Linux kernel, published on 4 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-2025-39937 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-2025-39937/ (Markdown: https://insights.sbomify.com/CVE-2025-39937/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39937
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39937
- OSV: https://osv.dev/vulnerability/CVE-2025-39937

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39937/
Summaries are generated and may contain mistakes; the official description above is the record.