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Response snapshot Oct 30, 2026, 19:11 UTC

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VulnerabilityCVE-2026-31486

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

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.

At a glance

Exploited
Not known
Severity
7.1 High (CVSS 3.1)
Chance of exploitation
<0.1% in the next 30 days
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-31486 (opens a new tab)

What happened

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.

Continue reading

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.

Scores and how they were measured

CVSS base severity

7.1

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

<0.1%

Scored Percentile 0.8%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-31486 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  5. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-31486, scored 2026-10-30. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 30). Linux kernel: hwmon: (pmbus/core) Protect regulator operations with mutex (CVE-2026-31486). https://kevwire.com/record/CVE-2026-31486

MLA

"Linux kernel: hwmon: (pmbus/core) Protect regulator operations with mutex (CVE-2026-31486)." KEVWire, 30 Oct. 2026, kevwire.com/record/CVE-2026-31486.

Chicago

KEVWire. "Linux kernel: hwmon: (pmbus/core) Protect regulator operations with mutex (CVE-2026-31486)." Last modified October 30, 2026. https://kevwire.com/record/CVE-2026-31486.

Evidence summary (plain text)

Linux kernel: hwmon: (pmbus/core) Protect regulator operations with mutex (Apr 22, 2026).
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.
CVSS 7.1 (version 3.1; evidence as of Oct 30, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-31486).
EPSS <0.1% for the following 30 days, scored Oct 30, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-31486&date=2026-10-30).
Sources:
NVD CVE-2026-31486: https://nvd.nist.gov/vuln/detail/CVE-2026-31486
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T13:06:45.042Z&lastModEndDate=2026-10-30T14:50:57.069Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T12:22:16.957Z&lastModEndDate=2026-10-30T14:05:57.373Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T11:45:59.009Z&lastModEndDate=2026-10-30T13:20:57.281Z&resultsPerPage=500&startIndex=0
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-31486&date=2026-10-30
Record ID: CVE-2026-31486.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 30, 2026, 14:52 UTC. Ingestion is not an independent editorial investigation.

NVD status: Modified. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

Record JSON

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Record details

Record detail