CVE-2026-80782: HID: magicmouse: do not keep a stale msc->input if no input is claimed

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

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

HID: magicmouse: do not keep a stale msc->input if no input is claimed

magicmouse_input_mapping() caches the first hid_input's input_dev in
msc->input while the report descriptor is parsed, and the rest of the
driver treats a non-NULL msc->input as proof that an input device was
registered.

That does not hold on the hid-input error path. If hidinput_connect()
fails -- for instance because input_register_device() returns an error --
it unwinds through hidinput_disconnect(), which frees every input_dev it
created, including the one cached in msc->input.

The failure does not abort the probe. hid_connect() only skips the claim:

	if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev,
				connect_mask & HID_CONNECT_HIDINPUT_FORCE))
		hdev->claimed |= HID_CLAIMED_INPUT;

and the "device has no listeners" bailout below it does not fire for this
driver, which sets ->raw_event; on the USB Magic Mouse 2 / Magic Trackpad
2 paths hidraw and hiddev are claimed as well. hid_hw_start() therefore
returns 0 and magicmouse_probe() continues with msc->input pointing at
freed memory. Being non-NULL, it passes the "input not registered" check
in probe and the NULL checks in ->raw_event and ->event, so the next
input report dereferences freed memory.

Clear msc->input when the HID core did not claim an input device, so the
existing NULL checks cover this case as well.

The Linux kernel CVE team has assigned CVE-2026-80782 to this issue.


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

	Issue introduced in 3.9 with commit f1a9a149abc86903e81dd1b2e720f3f89874384b and fixed in 5.10.269 with commit c3597923932bb90d4fc2186aef552f6677175e4a
	Issue introduced in 3.9 with commit f1a9a149abc86903e81dd1b2e720f3f89874384b and fixed in 5.15.218 with commit e0c224c93d10ee38854fdf24c815108aedd3dcb3
	Issue introduced in 3.9 with commit f1a9a149abc86903e81dd1b2e720f3f89874384b and fixed in 6.1.185 with commit 403cc9bd6ccb9fbe68d501c3236e5a6dd5504e14
	Issue introduced in 3.9 with commit f1a9a149abc86903e81dd1b2e720f3f89874384b and fixed in 6.6.154 with commit 3d7a7bac4c75f25b2513505a0ac5ba909588ed2b
	Issue introduced in 3.9 with commit f1a9a149abc86903e81dd1b2e720f3f89874384b and fixed in 6.12.106 with commit 9bdf8c7bfd79f1090e61d28f969b32880fd77bb3
	Issue introduced in 3.9 with commit f1a9a149abc86903e81dd1b2e720f3f89874384b and fixed in 6.18.47 with commit 15b60ade825c8ce9ec560048a4ae3747e4572be3
	Issue introduced in 3.9 with commit f1a9a149abc86903e81dd1b2e720f3f89874384b and fixed in 7.1.11 with commit 0bf253e9ac994cb5329bc87b00bb4eeca9136791
	Issue introduced in 3.9 with commit f1a9a149abc86903e81dd1b2e720f3f89874384b and fixed in 7.2.1 with commit 2ef16934e069d5f771e989d6ee5c3ece5042f3cd
	Issue introduced in 3.9 with commit f1a9a149abc86903e81dd1b2e720f3f89874384b and fixed in 7.3-rc1 with commit 0af3b89705688af01aa06025b84fa7a1e06ba6cc
	Issue introduced in 3.8.7 with commit 0e55072e7c63a6569cab1447e9025d160abd9dd9

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-2026-80782
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/hid/hid-magicmouse.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/c3597923932bb90d4fc2186aef552f6677175e4a
	https://git.kernel.org/stable/c/e0c224c93d10ee38854fdf24c815108aedd3dcb3
	https://git.kernel.org/stable/c/403cc9bd6ccb9fbe68d501c3236e5a6dd5504e14
	https://git.kernel.org/stable/c/3d7a7bac4c75f25b2513505a0ac5ba909588ed2b
	https://git.kernel.org/stable/c/9bdf8c7bfd79f1090e61d28f969b32880fd77bb3
	https://git.kernel.org/stable/c/15b60ade825c8ce9ec560048a4ae3747e4572be3
	https://git.kernel.org/stable/c/0bf253e9ac994cb5329bc87b00bb4eeca9136791
	https://git.kernel.org/stable/c/2ef16934e069d5f771e989d6ee5c3ece5042f3cd
	https://git.kernel.org/stable/c/0af3b89705688af01aa06025b84fa7a1e06ba6cc