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.
- 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
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
Which versions are affected by CVE-2025-39937?
It affects 1 product.
Products include 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
Sources
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 and 5 more.