# CVE-2026-31486

> Vulnerability · severity: **HIGH** (CVSS 7.1).

## Description

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

hwmon: (pmbus/core) Protect regulator operations with mutex

The regulator operations pmbus_regulator_get_voltage(),
pmbus_regulator_set_voltage(), and pmbus_regulator_list_voltage()
access PMBus registers and shared data but were not protected by
the update_lock mutex. This could lead to race conditions.

However, adding mutex protection directly to these functions causes
a deadlock because pmbus_regulator_notify() (which calls
regulator_notifier_call_chain()) is often called with the mutex
already held (e.g., from pmbus_fault_handler()). If a regulator
callback then calls one of the now-protected voltage functions,
it will attempt to acquire the same mutex.

Rework pmbus_regulator_notify() to utilize a worker function to
send notifications outside of the mutex protection. Events are
stored as atomics in a per-page bitmask and processed by the worker.

Initialize the worker and its associated data during regulator
registration, and ensure it is cancelled on device removal using
devm_add_action_or_reset().

While at it, remove the unnecessary include of linux/of.h.

## Key facts

- **CVE ID:** CVE-2026-31486
- **Published:** 2026-04-22
- **CVSS severity:** HIGH
- **CVSS base score:** 7.1
- **CWE codes:** CWE-667

## Affected products

- `linux:linux_kernel`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31486

## Citation

> AI Analytics. CVE-2026-31486. Retrieved 2026-07-20 from https://api.ai-analytics.org/cve/CVE-2026-31486. Derived from NIST NVD. Licensed CC0.

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