CVE-2026-31659

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

batman-adv: reject oversized global TT response buffers

batadv_tt_prepare_tvlv_global_data() builds the allocation length for a

global TT response in 16-bit temporaries. When a remote originator

advertises a large enough global TT, the TT payload length plus the VLAN

header offset can exceed 65535 and wrap before kmalloc().

The full-table response path still uses the original TT payload length when

it fills tt_change, so the wrapped allocation is too small and

batadv_tt_prepare_tvlv_global_data() writes past the end of the heap object

before the later packet-size check runs.

Fix this by rejecting TT responses whose TVLV value length cannot fit in

the 16-bit TVLV payload length field.