---
id: CVE-2026-31486
title: 'hwmon: (pmbus/core) Protect regulator operations with mutex'
summary: |-
  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_…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ddbb4db4ced1ba784fcd3500179a7291b6c5d7b7 <
    b26849cffaa7c43355b82e9bef3725e786973a1a
  - >-
    Linux >= ddbb4db4ced1ba784fcd3500179a7291b6c5d7b7 <
    acf04e2863132f6d9222f71f3a76fb9782cbe061
  - >-
    Linux >= ddbb4db4ced1ba784fcd3500179a7291b6c5d7b7 <
    4e9d723d9f198b86f6882a84c501ba1f39e8d055
  - >-
    Linux >= ddbb4db4ced1ba784fcd3500179a7291b6c5d7b7 <
    2c77ae315f3ce9d2c8e1609be74c9358c1fe4e07
  - >-
    Linux >= ddbb4db4ced1ba784fcd3500179a7291b6c5d7b7 <
    754bd2b4a084b90b5e7b630e1f423061a9b9b761
  - Linux 3.19
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-16T15:10:08.417028Z'
published: '2026-04-22'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:20:12.976Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-31486'
references:
  - url: 'https://git.kernel.org/stable/c/b26849cffaa7c43355b82e9bef3725e786973a1a'
  - url: 'https://git.kernel.org/stable/c/acf04e2863132f6d9222f71f3a76fb9782cbe061'
  - url: 'https://git.kernel.org/stable/c/4e9d723d9f198b86f6882a84c501ba1f39e8d055'
  - url: 'https://git.kernel.org/stable/c/2c77ae315f3ce9d2c8e1609be74c9358c1fe4e07'
  - url: 'https://git.kernel.org/stable/c/754bd2b4a084b90b5e7b630e1f423061a9b9b761'
tags:
  - cve.org
epss: 0.00099
epssPercentile: 0.0077
ingestedAt: '2026-10-16T17:24:46.656Z'
---

## Overview

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.

## Affected

- `Linux >= ddbb4db4ced1ba784fcd3500179a7291b6c5d7b7 < b26849cffaa7c43355b82e9bef3725e786973a1a`
- `Linux >= ddbb4db4ced1ba784fcd3500179a7291b6c5d7b7 < acf04e2863132f6d9222f71f3a76fb9782cbe061`
- `Linux >= ddbb4db4ced1ba784fcd3500179a7291b6c5d7b7 < 4e9d723d9f198b86f6882a84c501ba1f39e8d055`
- `Linux >= ddbb4db4ced1ba784fcd3500179a7291b6c5d7b7 < 2c77ae315f3ce9d2c8e1609be74c9358c1fe4e07`
- `Linux >= ddbb4db4ced1ba784fcd3500179a7291b6c5d7b7 < 754bd2b4a084b90b5e7b630e1f423061a9b9b761`
- `Linux 3.19`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.