CVE-2026-72234: batman-adv: access unicast_ttvn skb->data only after skb realloc

CVE-2026-72234: batman-adv: access unicast_ttvn skb->data only after skb realloc

[Greg Kroah-Hartman]

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

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

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

batman-adv: access unicast_ttvn skb->data only after skb realloc

The pskb_may_pull() called by batadv_get_vid() could reallocate the buffer
behind the skb. Variables which were pointing to the old buffer need to be
reassigned to avoid an use-after-free.

This was done correctly for the ethernet header but missed for the
unicast_packet pointer.

The Linux kernel CVE team has assigned CVE-2026-72234 to this issue.


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

	Issue introduced in 3.13 with commit c018ad3de61a1dc4194879a53e5559e094aa7b1a and fixed in 5.10.261 with commit aa9558af859934f24717d4bab97d61004f91a736
	Issue introduced in 3.13 with commit c018ad3de61a1dc4194879a53e5559e094aa7b1a and fixed in 5.15.212 with commit 9c2c05629e46c1fd43931506d41c56a885a98eb4
	Issue introduced in 3.13 with commit c018ad3de61a1dc4194879a53e5559e094aa7b1a and fixed in 6.1.178 with commit 7b162b36de750565404cd3b98315706622c6974f
	Issue introduced in 3.13 with commit c018ad3de61a1dc4194879a53e5559e094aa7b1a and fixed in 6.6.145 with commit ed90eb5c68420cdfe67ec1f773324198d2ef6f50
	Issue introduced in 3.13 with commit c018ad3de61a1dc4194879a53e5559e094aa7b1a and fixed in 6.12.97 with commit 979175834a699ccc3c4c0b0ba60ecae0f135a587
	Issue introduced in 3.13 with commit c018ad3de61a1dc4194879a53e5559e094aa7b1a and fixed in 6.18.40 with commit b8afcf799b2cc92c41beebd029e53ed18960184a
	Issue introduced in 3.13 with commit c018ad3de61a1dc4194879a53e5559e094aa7b1a and fixed in 7.1.5 with commit 9a7b7248798123efbd5fafe58461d57c7cc718af
	Issue introduced in 3.13 with commit c018ad3de61a1dc4194879a53e5559e094aa7b1a and fixed in 7.2-rc2 with commit 7141990add3f75436f2933cb310654cad3b1e3e9

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-2026-72234
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/routing.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/aa9558af859934f24717d4bab97d61004f91a736
	https://git.kernel.org/stable/c/9c2c05629e46c1fd43931506d41c56a885a98eb4
	https://git.kernel.org/stable/c/7b162b36de750565404cd3b98315706622c6974f
	https://git.kernel.org/stable/c/ed90eb5c68420cdfe67ec1f773324198d2ef6f50
	https://git.kernel.org/stable/c/979175834a699ccc3c4c0b0ba60ecae0f135a587
	https://git.kernel.org/stable/c/b8afcf799b2cc92c41beebd029e53ed18960184a
	https://git.kernel.org/stable/c/9a7b7248798123efbd5fafe58461d57c7cc718af
	https://git.kernel.org/stable/c/7141990add3f75436f2933cb310654cad3b1e3e9