CVE-2026-43457: mctp: i2c: fix skb memory leak in receive path

CVE-2026-43457: mctp: i2c: fix skb memory leak in receive path

[Greg Kroah-Hartman]

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

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

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

mctp: i2c: fix skb memory leak in receive path

When 'midev->allow_rx' is false, the newly allocated skb isn't consumed
by netif_rx(), it needs to free the skb directly.

The Linux kernel CVE team has assigned CVE-2026-43457 to this issue.


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

	Issue introduced in 5.18 with commit f5b8abf9fc3dacd7529d363e26fe8230935d65f8 and fixed in 6.1.167 with commit 0fb2adbdd5c03e8c9ebcdc48afd414b2724c85eb
	Issue introduced in 5.18 with commit f5b8abf9fc3dacd7529d363e26fe8230935d65f8 and fixed in 6.6.130 with commit d7900a43b0a314a645ca0a2adf45928dbc7001f4
	Issue introduced in 5.18 with commit f5b8abf9fc3dacd7529d363e26fe8230935d65f8 and fixed in 6.12.78 with commit 9f81be2ab9d8e4744871bfb3e868ef413413829f
	Issue introduced in 5.18 with commit f5b8abf9fc3dacd7529d363e26fe8230935d65f8 and fixed in 6.18.19 with commit 1ec54187e1aa40a4cfa2b265e9a311179f24b98d
	Issue introduced in 5.18 with commit f5b8abf9fc3dacd7529d363e26fe8230935d65f8 and fixed in 6.19.9 with commit 1b1be322342a6b0085bf6ee52235e5ac9834ec25
	Issue introduced in 5.18 with commit f5b8abf9fc3dacd7529d363e26fe8230935d65f8 and fixed in 7.0 with commit e3f5e0f22cfc2371e7471c9fd5b4da78f9df7c69

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-2026-43457
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/net/mctp/mctp-i2c.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/0fb2adbdd5c03e8c9ebcdc48afd414b2724c85eb
	https://git.kernel.org/stable/c/d7900a43b0a314a645ca0a2adf45928dbc7001f4
	https://git.kernel.org/stable/c/9f81be2ab9d8e4744871bfb3e868ef413413829f
	https://git.kernel.org/stable/c/1ec54187e1aa40a4cfa2b265e9a311179f24b98d
	https://git.kernel.org/stable/c/1b1be322342a6b0085bf6ee52235e5ac9834ec25
	https://git.kernel.org/stable/c/e3f5e0f22cfc2371e7471c9fd5b4da78f9df7c69