CVE-2026-72395: hwmon: (pmbus) Fix passing events to regulator core

CVE-2026-72395: hwmon: (pmbus) Fix passing events to regulator core

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

hwmon: (pmbus) Fix passing events to regulator core

Sashiko reports:

Commit 754bd2b4a084 ("hwmon: (pmbus/core) Protect regulator operations with
mutex") introduced a worker to batch regulator events over time using
atomic_or(). The delayed worker then passes the combined bitmask unmodified
to regulator_notifier_call_chain().

The core regulator subsystem's regulator_handle_critical() function
evaluates the event parameter using a strict switch statement. If
multiple distinct faults occur before the worker runs (e.g.,
REGULATOR_EVENT_UNDER_VOLTAGE | REGULATOR_EVENT_OVER_CURRENT), the combined
bitmask fails to match any case. This leaves the reason as NULL and
completely bypasses the critical hw_protection_trigger().

Fix the problem by passing events bit by bit to the regulator event
handler.

The Linux kernel CVE team has assigned CVE-2026-72395 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.6.143 with commit b26849cffaa7c43355b82e9bef3725e786973a1a and fixed in 6.6.145 with commit 2106bf4056858fcce3624e0c51f6fee4d41d3f2f
	Issue introduced in 6.12.92 with commit acf04e2863132f6d9222f71f3a76fb9782cbe061 and fixed in 6.12.97 with commit 48fe43666950efefb7ac5fbdc012c1b3604096bf
	Issue introduced in 6.18.21 with commit 4e9d723d9f198b86f6882a84c501ba1f39e8d055 and fixed in 6.18.40 with commit 489291b6b56978cc50d34e8e13f9636ea296ba8a
	Issue introduced in 7.0 with commit 754bd2b4a084b90b5e7b630e1f423061a9b9b761 and fixed in 7.1.5 with commit b0ff6b6ae9c5183ef701ece7016698bde5a5bfba
	Issue introduced in 7.0 with commit 754bd2b4a084b90b5e7b630e1f423061a9b9b761 and fixed in 7.2-rc2 with commit 9ef7dacd44216bf5ea05c8aef49eba4d145f4047
	Issue introduced in 6.19.11 with commit 2c77ae315f3ce9d2c8e1609be74c9358c1fe4e07

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-72395
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/hwmon/pmbus/pmbus_core.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/2106bf4056858fcce3624e0c51f6fee4d41d3f2f
	https://git.kernel.org/stable/c/48fe43666950efefb7ac5fbdc012c1b3604096bf
	https://git.kernel.org/stable/c/489291b6b56978cc50d34e8e13f9636ea296ba8a
	https://git.kernel.org/stable/c/b0ff6b6ae9c5183ef701ece7016698bde5a5bfba
	https://git.kernel.org/stable/c/9ef7dacd44216bf5ea05c8aef49eba4d145f4047