Bug 2516511 (CVE-2026-72397)

Summary:	CVE-2026-72397 kernel: hwmon: (pmbus/core) honor vrm_version in pmbus_data2reg_vid()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's `hwmon` subsystem, specifically within the `pmbus/core` module. The `pmbus_data2reg_vid()` function incorrectly hardcoded the VR11 encoding, disregarding the `vrm_version` configured by the driver. This issue could lead to drivers sending dangerously wrong voltage codes to the Power Management Bus (PMBus) `VOUT_COMMAND`, potentially causing hardware instability or damage due to incorrect voltage regulation.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-08-15 06:16:20 UTC

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.

Comment 1 gkamathe 2026-08-18 14:18:53 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081521-CVE-2026-72397-954f@gregkh/T