CVE-2026-64090: batman-adv: tt: avoid empty VLAN responses

From: Greg Kroah-Hartman <[email protected]>

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

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

batman-adv: tt: avoid empty VLAN responses

The commit 16116dac2339 ("batman-adv: prevent TT request storms by not
sending inconsistent TT TLVLs") added checks to the local (direct) TT
response code. But the response can also be done indirectly by another node
using the global TT state. To avoid such inconsistency states reported in
the original fix, also avoid sending empty VLANs for replies from the
global TT state.

The Linux kernel CVE team has assigned CVE-2026-64090 to this issue.


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

	Issue introduced in 3.13 with commit 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b and fixed in 5.10.259 with commit 1f467d9a095211d3f77e8ff1bee90e73ffe01c64
	Issue introduced in 3.13 with commit 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b and fixed in 5.15.210 with commit 9a02c8fc963ddeecb5d8788be0740c1869fc54b7
	Issue introduced in 3.13 with commit 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b and fixed in 6.1.176 with commit ea4f757641430bcc8322772e161453c4db5ecb64
	Issue introduced in 3.13 with commit 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b and fixed in 6.6.143 with commit 99f17d1cdb371cbd037975239b321f346d38f6d2
	Issue introduced in 3.13 with commit 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b and fixed in 6.12.93 with commit cfb30645280a2131e46cbd1b9a38cfd3ff893f12
	Issue introduced in 3.13 with commit 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b and fixed in 6.18.34 with commit b93ca6012712ecab2b551e120d7c95038d6a89e5
	Issue introduced in 3.13 with commit 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b and fixed in 7.0.11 with commit ab26e346322648f5c39de017d9723c9256284fce
	Issue introduced in 3.13 with commit 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b and fixed in 7.1 with commit fa1bd704940b5bcbc32c0b28db9167405c8ee5e0

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-2026-64090
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/translation-table.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/1f467d9a095211d3f77e8ff1bee90e73ffe01c64
	https://git.kernel.org/stable/c/9a02c8fc963ddeecb5d8788be0740c1869fc54b7
	https://git.kernel.org/stable/c/ea4f757641430bcc8322772e161453c4db5ecb64
	https://git.kernel.org/stable/c/99f17d1cdb371cbd037975239b321f346d38f6d2
	https://git.kernel.org/stable/c/cfb30645280a2131e46cbd1b9a38cfd3ff893f12
	https://git.kernel.org/stable/c/b93ca6012712ecab2b551e120d7c95038d6a89e5
	https://git.kernel.org/stable/c/ab26e346322648f5c39de017d9723c9256284fce
	https://git.kernel.org/stable/c/fa1bd704940b5bcbc32c0b28db9167405c8ee5e0