CVE-2022-50701: wifi: mt76: mt7921s: fix slab-out-of-bounds access in sdio host

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-12-24 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7921s: fix slab-out-of-bounds access in sdio host SDIO may need addtional 511 bytes to align bus operation. If the tailroom of this skb is not big enough, we would access invalid memory region. For low level operation, increase skb size to keep valid memory access in SDIO host. Error message: [69.951] BUG: KASAN: slab-out-of-bounds in sg_copy_buffer+0xe9/0x1a0 [69.951] Read of size 64 at addr ffff88811c9cf000 by task kworker/u16:7/451 [69.951] CPU: 4 PID: 451 Comm: kworker/u16:7 Tainted: G W OE 6.1.0-rc5 #1 [69.951] Workqueue: kvub300c vub300_cmndwork_thread [vub300] [69.951] Call Trace: [69.951] <TASK> [69.952] dump_stack_lvl+0x49/0x63 [69.952] print_report+0x171/0x4a8 [69.952] kasan_report+0xb4/0x130 [69.952] kasan_check_range+0x149/0x1e0 [69.952] memcpy+0x24/0x70 [69.952] sg_copy_buffer+0xe9/0x1a0 [69.952] sg_copy_to_buffer+0x12/0x20 [69.952] __command_write_data.isra.0+0x23c/0xbf0 [vub300] [69.952] vub300_cmndwork_thread+0x17f3/0x58b0 [vub300] [69.952] process_one_work+0x7ee/0x1320 [69.952] worker_thread+0x53c/0x1240 [69.952] kthread+0x2b8/0x370 [69.952] ret_from_fork+0x1f/0x30 [69.952] </TASK> [69.952] Allocated by task 854: [69.952] kasan_save_stack+0x26/0x50 [69.952] kasan_set_track+0x25/0x30 [69.952] kasan_save_alloc_info+0x1b/0x30 [69.952] __kasan_kmalloc+0x87/0xa0 [69.952] __kmalloc_node_track_caller+0x63/0x150 [69.952] kmalloc_reserve+0x31/0xd0 [69.952] __alloc_skb+0xfc/0x2b0 [69.952] __mt76_mcu_msg_alloc+0xbf/0x230 [mt76] [69.952] mt76_mcu_send_and_get_msg+0xab/0x110 [mt76] [69.952] __mt76_mcu_send_firmware.cold+0x94/0x15d [mt76] [69.952] mt76_connac_mcu_send_ram_firmware+0x415/0x54d [mt76_connac_lib] [69.952] mt76_connac2_load_ram.cold+0x118/0x4bc [mt76_connac_lib] [69.952] mt7921_run_firmware.cold+0x2e9/0x405 [mt7921_common] [69.952] mt7921s_mcu_init+0x45/0x80 [mt7921s] [69.953] mt7921_init_work+0xe1/0x2a0 [mt7921_common] [69.953] process_one_work+0x7ee/0x1320 [69.953] worker_thread+0x53c/0x1240 [69.953] kthread+0x2b8/0x370 [69.953] ret_from_fork+0x1f/0x30 [69.953] The buggy address belongs to the object at ffff88811c9ce800 which belongs to the cache kmalloc-2k of size 2048 [69.953] The buggy address is located 0 bytes to the right of 2048-byte region [ffff88811c9ce800, ffff88811c9cf000) [69.953] Memory state around the buggy address: [69.953] ffff88811c9cef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [69.953] ffff88811c9cef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [69.953] >ffff88811c9cf000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [69.953] ^ [69.953] ffff88811c9cf080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [69.953] ffff88811c9cf100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

Affected products

Linux kernel: 5.16 — fixed in 6.3

How to fix

Upgrade to a fixed version: Linux kernel 6.3. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2022-50701 or the next vulnerability affects your stack