CVE-2025-40224

Vulnerability

The cgbc-hwmon driver in the Linux kernel allocates memory for sensor data using devm_kzalloc() but does not validate the return value. If memory allocation fails, devm_kzalloc() returns NULL, and subsequent dereference of the sensor data pointer leads to a NULL pointer dereference, resulting in a kernel crash [1].

Exploitation

Exploitation requires triggering a memory allocation failure in the kernel, which can occur under low-memory conditions or through controlled resource exhaustion. The attack surface is local; an unprivileged user may be able to cause memory pressure to induce the failure. No authentication is required beyond local access to the system [1].

Impact

Successful exploitation causes a denial of service via kernel panic. The vulnerability does not provide code execution or privilege escalation; the impact is limited to system availability [1].

Mitigation

The fix adds a NULL check after devm_kzalloc() and returns -ENOMEM on allocation failure. The patch was committed to the Linux kernel stable tree and is available at the referenced commit [1]. Users should apply kernel updates that include this commit.