CVE-2026-53230

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

net/mlx5: Fix slab-out-of-bounds in mlx5_query_nic_vport_mac_list

mlx5_query_nic_vport_mac_list() sizes its firmware command buffer using

the PF's log_max_current_uc/mc_list capabilities. When querying a VF

vport with a larger configured max (via devlink), the firmware response

can overflow this buffer:

BUG: KASAN: slab-out-of-bounds in mlx5_query_nic_vport_mac_list+0x453/0x4c0 [mlx5_core]

Read of size 4 at addr ff1100013ffc8a12 by task kworker/u96:2/385

CPU: 12 UID: 0 PID: 385 Comm: kworker/u96:2 Not tainted 7.0.0-rc6+ #1 PREEMPT

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)

Workqueue: mlx5_esw_wq esw_vport_change_handler [mlx5_core]

Call Trace:

<TASK>

dump_stack_lvl+0x69/0xa0

print_report+0x176/0x4e4

kasan_report+0xc8/0x100

mlx5_query_nic_vport_mac_list+0x453/0x4c0 [mlx5_core]

esw_update_vport_addr_list+0x2e3/0xda0 [mlx5_core]

esw_vport_change_handle_locked+0xa1f/0x1060 [mlx5_core]

esw_vport_change_handler+0x6a/0x90 [mlx5_core]

process_one_work+0x87f/0x15e0

worker_thread+0x62b/0x1020

kthread+0x375/0x490

ret_from_fork+0x4dc/0x810

ret_from_fork_asm+0x11/0x20

</TASK>

Fix by querying the vport's own HCA caps to size the buffer correctly.

Refactor the function to allocate and return the MAC list internally,

removing the caller's dependency on knowing the correct max.