CVE-2026-68314: net: mctp i3c: clean up notifier and buses if driver register fails

CVE-2026-68314: net: mctp i3c: clean up notifier and buses if driver register fails

[Greg Kroah-Hartman]

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

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

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

net: mctp i3c: clean up notifier and buses if driver register fails

mctp_i3c_mod_init() registers the I3C bus notifier and then walks the
existing buses with i3c_for_each_bus_locked(mctp_i3c_bus_add_new, NULL)
before registering the I3C device driver.  If i3c_driver_register()
fails, the function returns the error directly, leaving the notifier
registered and every mctp_i3c_bus object created for the existing buses
allocated.  The notifier is left pointing into the module that failed to
load and the bus list is leaked.

Mirror the module exit path on this failure: unregister the notifier and
tear down the buses that were added before returning the error.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

The Linux kernel CVE team has assigned CVE-2026-68314 to this issue.


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

	Issue introduced in 6.7 with commit c8755b29b58ec65be17bcb8c40763d2dcb1f1db5 and fixed in 6.12.101 with commit 49d15cfab247c0f60ce1800bdcd66850beea7b3a
	Issue introduced in 6.7 with commit c8755b29b58ec65be17bcb8c40763d2dcb1f1db5 and fixed in 6.18.42 with commit a8bd8c109da5a87f0c5db0c23cf550d039fde77c
	Issue introduced in 6.7 with commit c8755b29b58ec65be17bcb8c40763d2dcb1f1db5 and fixed in 7.1.6 with commit a40e83a34eaa2be64372286040696f04eabcd09f
	Issue introduced in 6.7 with commit c8755b29b58ec65be17bcb8c40763d2dcb1f1db5 and fixed in 7.2-rc5 with commit 03d1057305ef17ac3f5936ac1580bc9a1a826e14

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-2026-68314
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-i3c.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/49d15cfab247c0f60ce1800bdcd66850beea7b3a
	https://git.kernel.org/stable/c/a8bd8c109da5a87f0c5db0c23cf550d039fde77c
	https://git.kernel.org/stable/c/a40e83a34eaa2be64372286040696f04eabcd09f
	https://git.kernel.org/stable/c/03d1057305ef17ac3f5936ac1580bc9a1a826e14