CVE-2026-80574: Input: focaltech - fix array out-of-bounds in focaltech_process_rel_packet

CVE-2026-80574: Input: focaltech - fix array out-of-bounds in focaltech_process_rel_packet

[Greg Kroah-Hartman]

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

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

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

Input: focaltech - fix array out-of-bounds in focaltech_process_rel_packet

Make finger2 (and also finger1) unsigned, so that if the finger index in
the packet is 0 then subtracting 1 creates an array index which overflows
above the existing check for FOC_MAX_FINGERS, as the existing comment says
it should, instead of writing to state->fingers[-1].

The Linux kernel CVE team has assigned CVE-2026-80574 to this issue.


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

	Issue introduced in 4.0 with commit 05be1d079ec0b3691783e4384b1ada82149ff7d2 and fixed in 5.10.266 with commit 063b4c6a6f3fc01bca085c442000c9c100fdbd93
	Issue introduced in 4.0 with commit 05be1d079ec0b3691783e4384b1ada82149ff7d2 and fixed in 5.15.217 with commit bb502d79acb9ac1e0a77fa8bc7b7b4729140b11f
	Issue introduced in 4.0 with commit 05be1d079ec0b3691783e4384b1ada82149ff7d2 and fixed in 6.1.184 with commit ca92c98b806839c108995b2bbff7061515bdfb53
	Issue introduced in 4.0 with commit 05be1d079ec0b3691783e4384b1ada82149ff7d2 and fixed in 6.6.153 with commit 81b07470cb2937ceb74b00be88151582a322433b
	Issue introduced in 4.0 with commit 05be1d079ec0b3691783e4384b1ada82149ff7d2 and fixed in 6.12.105 with commit 6f6d5fe29efdf5001bc146fc292e6592cace93eb
	Issue introduced in 4.0 with commit 05be1d079ec0b3691783e4384b1ada82149ff7d2 and fixed in 6.18.46 with commit 83c265bfc084d77e2171d4b67362150ab38c935b
	Issue introduced in 4.0 with commit 05be1d079ec0b3691783e4384b1ada82149ff7d2 and fixed in 7.1.10 with commit 1842e47126816e56d30c4f856f9854fd7831066c
	Issue introduced in 4.0 with commit 05be1d079ec0b3691783e4384b1ada82149ff7d2 and fixed in 7.2 with commit 296736076b3fd078742651c719555a488624023a

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-2026-80574
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/input/mouse/focaltech.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/063b4c6a6f3fc01bca085c442000c9c100fdbd93
	https://git.kernel.org/stable/c/bb502d79acb9ac1e0a77fa8bc7b7b4729140b11f
	https://git.kernel.org/stable/c/ca92c98b806839c108995b2bbff7061515bdfb53
	https://git.kernel.org/stable/c/81b07470cb2937ceb74b00be88151582a322433b
	https://git.kernel.org/stable/c/6f6d5fe29efdf5001bc146fc292e6592cace93eb
	https://git.kernel.org/stable/c/83c265bfc084d77e2171d4b67362150ab38c935b
	https://git.kernel.org/stable/c/1842e47126816e56d30c4f856f9854fd7831066c
	https://git.kernel.org/stable/c/296736076b3fd078742651c719555a488624023a