CVE-2026-64126

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

Bluetooth: MGMT: validate Add Extended Advertising Data length

MGMT_OP_ADD_EXT_ADV_DATA is registered as a variable-length command,

with MGMT_ADD_EXT_ADV_DATA_SIZE as the fixed header size. The handler

then uses cp->adv_data_len and cp->scan_rsp_len to validate and copy

cp->data, but it never checks that those bytes are part of the mgmt

command payload.

A short command can therefore make add_ext_adv_data() pass an

out-of-bounds pointer into tlv_data_is_valid(). If the bytes beyond

the command buffer are addressable, they can also be copied into the

advertising instance as scan response data, where the caller can read

them back via MGMT_OP_GET_ADV_INSTANCE. The trigger requires

CAP_NET_ADMIN in the initial user namespace; KASAN reports an 8-byte

slab-out-of-bounds read.

Reject commands whose length does not match the fixed header plus both

advertising data lengths before parsing cp->data.