CVE-2025-39937: linux kernel Null Dereference — Fix

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

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	4.6 — 5.4.300
linux	linux_kernel	5.5 — 5.10.245
linux	linux_kernel	5.11 — 5.15.194
linux	linux_kernel	5.16 — 6.1.154
linux	linux_kernel	6.2 — 6.6.108
linux	linux_kernel	6.7 — 6.12.49
linux	linux_kernel	6.13 — 6.16.9
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/184f608a68f96794e8fe58cd5535014d53622cde https://git.kernel.org/stable/c/21a39b958b4bcf44f7674bfbbe1bbb8cad0d842d https://git.kernel.org/stable/c/21ba85d9d508422ca9e6698463ff9357c928c22d https://git.kernel.org/stable/c/47ade5f9d70b23a119ec20b1c6504864b2543a79 https://git.kernel.org/stable/c/689aee35ce671aab752f159e5c8e66d7685e6887 https://git.kernel.org/stable/c/8793e7a8e1b60131a825457174ed6398111daeb7 https://git.kernel.org/stable/c/ada2282259243387e6b6e89239aeb4897e62f051 https://git.kernel.org/stable/c/b6f56a44e4c1014b08859dcf04ed246500e310e5

Frequently Asked Questions

What is CVE-2025-39937? +

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 It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-39937? +

CVE-2025-39937 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-39937? +

CVE-2025-39937 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-39937? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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