CVE-2026-72308: mlxsw: fix refcount leak in mlxsw_sp_port_lag_join()

CVE-2026-72308: mlxsw: fix refcount leak in mlxsw_sp_port_lag_join()

[Greg Kroah-Hartman]

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

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

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

mlxsw: fix refcount leak in mlxsw_sp_port_lag_join()

When mlxsw_sp_port_lag_index_get() fails, mlxsw_sp_port_lag_join()
returns an error without releasing the lag reference obtained by
the earlier mlxsw_sp_lag_get().  All other error paths in the
function jump to the cleanup label that ends with
mlxsw_sp_lag_put(), so this is a single missed release.

Fix the leak by replacing the bare 'return err' with a goto to the
existing error cleanup label, which will drop the reference safely.

The Linux kernel CVE team has assigned CVE-2026-72308 to this issue.


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

	Issue introduced in 4.5 with commit 0d65fc13042fce6a2d6de58ff0dc9531e8523c07 and fixed in 6.6.145 with commit 8b3350eacd9df0597bfe36a594df7b9def0b3edf
	Issue introduced in 4.5 with commit 0d65fc13042fce6a2d6de58ff0dc9531e8523c07 and fixed in 6.12.97 with commit 1cf8a1af42b1f12a30b7abd34fe4fc23b3170e7e
	Issue introduced in 4.5 with commit 0d65fc13042fce6a2d6de58ff0dc9531e8523c07 and fixed in 6.18.40 with commit 2d8b3c3e129973a51ae924bdcf6993a76b828814
	Issue introduced in 4.5 with commit 0d65fc13042fce6a2d6de58ff0dc9531e8523c07 and fixed in 7.1.5 with commit cab468c3c03f4bcd7530ce2783a4140da14efb7b
	Issue introduced in 4.5 with commit 0d65fc13042fce6a2d6de58ff0dc9531e8523c07 and fixed in 7.2-rc1 with commit 41c8c1d65b32beacd8d916a22457b4f6e47f45af

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-2026-72308
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/ethernet/mellanox/mlxsw/spectrum.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/8b3350eacd9df0597bfe36a594df7b9def0b3edf
	https://git.kernel.org/stable/c/1cf8a1af42b1f12a30b7abd34fe4fc23b3170e7e
	https://git.kernel.org/stable/c/2d8b3c3e129973a51ae924bdcf6993a76b828814
	https://git.kernel.org/stable/c/cab468c3c03f4bcd7530ce2783a4140da14efb7b
	https://git.kernel.org/stable/c/41c8c1d65b32beacd8d916a22457b4f6e47f45af