CVE-2026-72397
Received Received - Intake

PMBus Core VRM Version Handling Flaw in Linux Kernel

Publication date: 2026-08-15

Last updated on: 2026-08-15

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/core) honor vrm_version in pmbus_data2reg_vid() pmbus_data2reg_vid() hardcoded the VR11 encoding regardless of the vrm_version configured by the driver, while pmbus_reg2data_vid() already switched on it. Any driver that selects a non-VR11 VID mode and exposes a regulator (or hwmon vout setter) sent dangerously wrong codes to PMBUS_VOUT_COMMAND -- e.g. an nvidia195mv part asked for 200 mV got the VR11 clamp to 500 mV encoded as 0xB2, which the chip interprets as 1080 mV. Mirror pmbus_reg2data_vid() so writes round-trip with reads.

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Meta Information

Published
2026-08-15
Last Modified
2026-08-15
Generated
2026-08-15
AI Q&A
2026-08-15
EPSS Evaluated
N/A
NVD
CVE-2026-72397
EUVD
EUVD-2026-59296

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel affects the hwmon subsystem, specifically the pmbus driver. The function pmbus_data2reg_vid() incorrectly hardcoded the VR11 encoding for voltage regulation, ignoring the vrm_version set by the driver. This caused incorrect voltage commands to be sent to hardware, leading to potential misinterpretation of voltage settings by the chip.

Detection Guidance

This vulnerability is specific to the Linux kernel's hwmon subsystem and PMBus functionality. Detection requires checking kernel logs for PMBus-related errors or examining driver configurations for incorrect VRM version handling. No direct network detection commands are applicable.

Impact Analysis

If you use a system with a vulnerable Linux kernel and a PMBus-compatible hardware component (like a regulator or voltage controller), this flaw could cause incorrect voltage levels to be applied. For example, requesting 200 mV might result in the chip interpreting it as 1080 mV, potentially damaging hardware or causing system instability.

Mitigation Strategies

Update the Linux kernel to a patched version that resolves this issue. Monitor vendor advisories for PMBus driver updates. If using affected hardware, verify regulator output settings match expected values to prevent incorrect voltage commands.

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