CVE-2026-74711

In the Linux kernel, the following vulnerability has been resolved:

hwmon: (pmbus) Fix type confusion in notification logic

Sashiko reports:

At the start of the loop in pmbus_notify(), the code unconditionally casts

every attribute to a struct sensor_device_attribute:

drivers/hwmon/pmbus/pmbus_core.c:pmbus_notify() {

for (i = 0; i < data->num_attributes; i++) {

struct device_attribute *da = to_dev_attr(data->group.attrs[i]);

struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

int index = attr->index;

...

}

However, data->group.attrs can contain other types like struct

pmbus_samples_reg or struct pmbus_sensor, which only embed a base

struct device_attribute.

If da is a struct pmbus_samples_reg, dev_attr is the last member. Casting

it to struct sensor_device_attribute and reading the index field appears

to access memory past the end of the allocation, which might trigger a

slab-out-of-bounds read.

Additionally, if da is a struct pmbus_sensor, casting it causes the index

field to overlap with the page, phase, and reg fields. Could this produce

a garbage mask on little-endian systems that spuriously matches the target

reg, page, and flags during an alert?

Fix the problem by using struct sensor_device_attr in struct pmbus_sensor

and struct pmbus_label. Since those attributes never trigger a

notification, set the value of attr->index to -1 for them. Use this value

to distinguish from boolean attributes which _can_ trigger a notification

and use the index field to encode mask, page, and register values.