Linux Kernel up to 6.18.20/6.19.10 pmbus_regulator_get_voltage race condition

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CTI Interest Score
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Summaryinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.18.20/6.19.10. The affected element is the function pmbus_regulator_get_voltage. Such manipulation leads to race condition. This vulnerability is uniquely identified as CVE-2026-31486. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.20/6.19.10. It has been rated as critical. Affected by this issue is the function pmbus_regulator_get_voltage. The manipulation with an unknown input leads to a race condition vulnerability. Using CWE to declare the problem leads to CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. The impact remains unknown. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-31486 since 03/09/2026. The exploitation is known to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 321868 (Debian dsa-6355 : ata-modules-6.12.90+deb13-armmp-di - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.21 or 6.19.11 eliminates this vulnerability. Applying the patch 4e9d723d9f198b86f6882a84c501ba1f39e8d055/2c77ae315f3ce9d2c8e1609be74c9358c1fe4e07/754bd2b4a084b90b5e7b630e1f423061a9b9b761 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (321868) and CERT Bund (WID-SEC-2026-1252). Once again VulDB remains the best source for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel
  • Siemens SIMATIC S7
  • Proxmox Virtual Environment

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.8
VulDB Meta Temp Score: 5.7

VulDB Base Score: 4.6
VulDB Temp Score: 4.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.1
CNA Vector (Linux): 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Race condition
CWE: CWE-362
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 321868
Nessus Name: Debian dsa-6355 : ata-modules-6.12.90+deb13-armmp-di - security update

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.21/6.19.11
Patch: 4e9d723d9f198b86f6882a84c501ba1f39e8d055/2c77ae315f3ce9d2c8e1609be74c9358c1fe4e07/754bd2b4a084b90b5e7b630e1f423061a9b9b761

Timelineinfo

03/09/2026 CVE reserved
04/22/2026 +43 days Advisory disclosed
04/22/2026 +0 days VulDB entry created
07/25/2026 +94 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-31486 (🔒)
GCVE (CVE): GCVE-0-2026-31486
GCVE (VulDB): GCVE-100-358892
CERT Bund: WID-SEC-2026-1252 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 04/22/2026 17:10
Updated: 07/25/2026 20:24
Changes: 04/22/2026 17:10 (58), 06/03/2026 10:12 (11), 06/18/2026 00:31 (7), 06/21/2026 21:51 (2), 07/25/2026 20:24 (3)
Complete: 🔍
Cache ID: 216::103

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