CVE-2026-72229: batman-adv: clean untagged VLAN on netdev registration failure

CVE-2026-72229: batman-adv: clean untagged VLAN on netdev registration failure

[Greg Kroah-Hartman]

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

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

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

batman-adv: clean untagged VLAN on netdev registration failure

When an mesh interface is registered, it creates an untagged struct
batadv_meshif_vlan on top of it via the NETDEV_REGISTER notifier. But in
this process, another receiver of this notification can veto the
registration. The netdev registration will be aborted because of this veto.

The register_netdevice() call will try to clean up the net_device using
unregister_netdevice_queue() - which only uses the .priv_destructor to
free private resources. In this situation, .dellink will not be called.

The cleanup of the untagged batadv_meshif_vlan must thefore be done in the
destructor to avoid a leak of this object.

The Linux kernel CVE team has assigned CVE-2026-72229 to this issue.


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

	Issue introduced in 3.13 with commit 5d2c05b213377694a2aa8ce1ed9b23f7c39b0569 and fixed in 5.10.261 with commit 86e32dfb6a6fe29898f4a562b7b6e38e480bba4d
	Issue introduced in 3.13 with commit 5d2c05b213377694a2aa8ce1ed9b23f7c39b0569 and fixed in 5.15.212 with commit 06ae245168268b705a204f93c318b30107d10e92
	Issue introduced in 3.13 with commit 5d2c05b213377694a2aa8ce1ed9b23f7c39b0569 and fixed in 6.1.178 with commit dbca15fcbeed5276af440a53aed3901590fa7fc9
	Issue introduced in 3.13 with commit 5d2c05b213377694a2aa8ce1ed9b23f7c39b0569 and fixed in 6.6.145 with commit f2423da55976ea249f73029e468aefda4b94acba
	Issue introduced in 3.13 with commit 5d2c05b213377694a2aa8ce1ed9b23f7c39b0569 and fixed in 6.12.97 with commit f15ca6250591cfe78408114a54eaa8d58da51bfa
	Issue introduced in 3.13 with commit 5d2c05b213377694a2aa8ce1ed9b23f7c39b0569 and fixed in 6.18.40 with commit c945f6007e7851e74706c72f98763023699bcd97
	Issue introduced in 3.13 with commit 5d2c05b213377694a2aa8ce1ed9b23f7c39b0569 and fixed in 7.1.5 with commit 5a82c558098889cc8bfff85cc62f563833205d91
	Issue introduced in 3.13 with commit 5d2c05b213377694a2aa8ce1ed9b23f7c39b0569 and fixed in 7.2-rc3 with commit 8669a550c752d86baebc5fdc83b8ff35c4372c0e

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-2026-72229
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:
	net/batman-adv/main.c
	net/batman-adv/mesh-interface.c
	net/batman-adv/mesh-interface.h


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/86e32dfb6a6fe29898f4a562b7b6e38e480bba4d
	https://git.kernel.org/stable/c/06ae245168268b705a204f93c318b30107d10e92
	https://git.kernel.org/stable/c/dbca15fcbeed5276af440a53aed3901590fa7fc9
	https://git.kernel.org/stable/c/f2423da55976ea249f73029e468aefda4b94acba
	https://git.kernel.org/stable/c/f15ca6250591cfe78408114a54eaa8d58da51bfa
	https://git.kernel.org/stable/c/c945f6007e7851e74706c72f98763023699bcd97
	https://git.kernel.org/stable/c/5a82c558098889cc8bfff85cc62f563833205d91
	https://git.kernel.org/stable/c/8669a550c752d86baebc5fdc83b8ff35c4372c0e