CVE-2026-72235: batman-adv: retrieve ethhdr after potential skb realloc on RX

CVE-2026-72235: batman-adv: retrieve ethhdr after potential skb realloc on RX

[Greg Kroah-Hartman]

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

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

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

batman-adv: retrieve ethhdr after potential skb realloc on RX

pskb_may_pull() in batadv_interface_rx() 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 VLAN header but missed for the ethernet
header which is later used for the TT and AP isolation handling.

The Linux kernel CVE team has assigned CVE-2026-72235 to this issue.


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

	Issue introduced in 2.6.38 with commit c6c8fea29769d998d94fcec9b9f14d4b52b349d3 and fixed in 5.10.261 with commit 6e189f14d1ea28db212b9d70a02131a7ce518012
	Issue introduced in 2.6.38 with commit c6c8fea29769d998d94fcec9b9f14d4b52b349d3 and fixed in 5.15.212 with commit a1820344b180cb55af748f102bc536b5c93164db
	Issue introduced in 2.6.38 with commit c6c8fea29769d998d94fcec9b9f14d4b52b349d3 and fixed in 6.1.178 with commit 6abf73589bed3f27ee240c08108feb72bed0b9c6
	Issue introduced in 2.6.38 with commit c6c8fea29769d998d94fcec9b9f14d4b52b349d3 and fixed in 6.6.145 with commit f19259395b44af67f3c274e34237c295b526b859
	Issue introduced in 2.6.38 with commit c6c8fea29769d998d94fcec9b9f14d4b52b349d3 and fixed in 6.12.97 with commit 2cefa5141cab8ec1e4b24cf585958b13f2e3049d
	Issue introduced in 2.6.38 with commit c6c8fea29769d998d94fcec9b9f14d4b52b349d3 and fixed in 6.18.40 with commit 85a71a81854e0e191ad0e533eabb4eff54866feb
	Issue introduced in 2.6.38 with commit c6c8fea29769d998d94fcec9b9f14d4b52b349d3 and fixed in 7.1.5 with commit b031fc97e1993d29d6c3a0e86a99140528cf31e8
	Issue introduced in 2.6.38 with commit c6c8fea29769d998d94fcec9b9f14d4b52b349d3 and fixed in 7.2-rc2 with commit 035e1fed892d3d06002a73ff73668f618a514644

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-2026-72235
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/mesh-interface.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/6e189f14d1ea28db212b9d70a02131a7ce518012
	https://git.kernel.org/stable/c/a1820344b180cb55af748f102bc536b5c93164db
	https://git.kernel.org/stable/c/6abf73589bed3f27ee240c08108feb72bed0b9c6
	https://git.kernel.org/stable/c/f19259395b44af67f3c274e34237c295b526b859
	https://git.kernel.org/stable/c/2cefa5141cab8ec1e4b24cf585958b13f2e3049d
	https://git.kernel.org/stable/c/85a71a81854e0e191ad0e533eabb4eff54866feb
	https://git.kernel.org/stable/c/b031fc97e1993d29d6c3a0e86a99140528cf31e8
	https://git.kernel.org/stable/c/035e1fed892d3d06002a73ff73668f618a514644