CVE-2026-43375: net: mctp: fix device leak on probe failure

CVE-2026-43375: net: mctp: fix device leak on probe failure

[Greg Kroah-Hartman]

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

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

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

net: mctp: fix device leak on probe failure

Driver core holds a reference to the USB interface and its parent USB
device while the interface is bound to a driver and there is no need to
take additional references unless the structures are needed after
disconnect.

This driver takes a reference to the USB device during probe but does
not to release it on probe failures.

Drop the redundant device reference to fix the leak, reduce cargo
culting, make it easier to spot drivers where an extra reference is
needed, and reduce the risk of further memory leaks.

The Linux kernel CVE team has assigned CVE-2026-43375 to this issue.


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

	Issue introduced in 6.15 with commit 0791c0327a6e4e7691d6fc5ad334c215de04dcc9 and fixed in 6.18.19 with commit 3224990fb16a831aabc50b67c74f5d0074ce80dd
	Issue introduced in 6.15 with commit 0791c0327a6e4e7691d6fc5ad334c215de04dcc9 and fixed in 6.19.9 with commit ec9538f9b5cd1db5e8c612aa636b6119b6355c5d
	Issue introduced in 6.15 with commit 0791c0327a6e4e7691d6fc5ad334c215de04dcc9 and fixed in 7.0 with commit 224a0d284c3caf1951302d1744a714784febed71

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-2026-43375
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-usb.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/3224990fb16a831aabc50b67c74f5d0074ce80dd
	https://git.kernel.org/stable/c/ec9538f9b5cd1db5e8c612aa636b6119b6355c5d
	https://git.kernel.org/stable/c/224a0d284c3caf1951302d1744a714784febed71