CVE-2026-81017: platform/chrome: sensorhub: Bound the EC-reported sensor number

CVE-2026-81017: platform/chrome: sensorhub: Bound the EC-reported sensor number

[Greg Kroah-Hartman]

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

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

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

platform/chrome: sensorhub: Bound the EC-reported sensor number

Each EC FIFO event carries an 8-bit sensor number (in->sensor_num).
cros_ec_sensorhub_ring_handler() validates the FIFO event count, the
per-read count and the ring bound, but not the sensor number, which
cros_ec_sensor_ring_process_event() then uses unchecked to index
sensorhub->batch_state[] - allocated with only sensorhub->sensor_num
entries. A sensor number of sensor_num or larger is an out-of-bounds
read and write of batch_state[].

Validate the sensor number in the ring handler, where each event is read
from the EC, and drop a malformed event before it is used.

The Linux kernel CVE team has assigned CVE-2026-81017 to this issue.


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

	Issue introduced in 5.7 with commit 145d59baff5944b71551ac518d7fd7d377a9c820 and fixed in 6.12.109 with commit 3d2636dce0a8fe9eecad29010699847be425dc80
	Issue introduced in 5.7 with commit 145d59baff5944b71551ac518d7fd7d377a9c820 and fixed in 6.18.50 with commit 5eaf7faa99578ae090030d1e2e6ea3b37a615496
	Issue introduced in 5.7 with commit 145d59baff5944b71551ac518d7fd7d377a9c820 and fixed in 7.2.4 with commit 4d9bf63ed74f859c6698bc01d8fb216ef9253867
	Issue introduced in 5.7 with commit 145d59baff5944b71551ac518d7fd7d377a9c820 and fixed in 7.3-rc1 with commit 833740a2333c2e4db4e02e3d0ffba04e8718a5f3

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-2026-81017
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/platform/chrome/cros_ec_sensorhub_ring.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/3d2636dce0a8fe9eecad29010699847be425dc80
	https://git.kernel.org/stable/c/5eaf7faa99578ae090030d1e2e6ea3b37a615496
	https://git.kernel.org/stable/c/4d9bf63ed74f859c6698bc01d8fb216ef9253867
	https://git.kernel.org/stable/c/833740a2333c2e4db4e02e3d0ffba04e8718a5f3