CVE-2026-74711: hwmon: (pmbus) Fix type confusion in notification logic

Severity: high (CVSS 8.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-22 · updated 2026-10-21

Description

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.

Affected products

Linux kernel: 6.4 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux kernel 7.2. Check the vendor advisory for mitigations.

References

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