CVE-2022-50701: wifi: mt76: mt7921s: fix slab-out-of-bounds access in sdio host
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
Security readout for executives and security teams
Plain-English summary
CVE-2022-50701 is a Linux kernel memory-safety issue in the mt76 driver path for MediaTek MT7921S SDIO Wi-Fi. The source shows an out-of-bounds memory read when SDIO alignment needs extra tailroom. Business urgency depends on whether your Linux systems use this specific wireless driver and kernel range.
Executive priority
Treat as targeted operational risk rather than broad emergency until affected hardware is confirmed. Patch through normal kernel maintenance, but accelerate for fleets with MT7921S SDIO Wi-Fi or embedded Linux exposure.
Technical view
The flaw is a slab-out-of-bounds access in the Linux mt76 mt7921s SDIO host path. The described cause is insufficient skb tailroom when SDIO bus operations need up to 511 extra alignment bytes. The upstream resolution increases skb size for valid low-level SDIO memory access.
Likely exposure
Exposure appears limited to Linux systems using the mt76 mt7921s SDIO Wi-Fi driver path, especially kernels identified in the CVE affected data. Servers without this hardware or driver loaded are less likely to be exposed.
Exploitation context
The bundle does not show KEV listing, public exploitation, weaponized details, or remote attack evidence. It provides a KASAN crash trace and upstream kernel fixes, so exploitation status should be treated as unconfirmed.
Researcher notes
The evidence is kernel-source centric: cause, crash trace, allocation path, and stable commit references are available. CVSS, CWE, exploitability, and downstream vendor package status are not provided in the bundle.
Mitigation direction
Apply a vendor or upstream stable Linux kernel containing the referenced fixes.
Check distribution advisories for backported fixes matching your deployed kernel.
Prioritize systems with MT7921S SDIO Wi-Fi enabled or the mt7921s module loaded.
If unneeded, consider disabling affected hardware or driver per vendor guidance.
Validation and detection
Inventory Linux kernel versions across laptops, embedded devices, and appliances.
Check whether mt76, mt7921_common, or mt7921s modules are present or loaded.
Map deployed kernels against vendor advisories and the linked stable commits.
Review kernel logs for related KASAN or slab-out-of-bounds reports.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Potential ATT&CK relevance
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
cve · low confidence lookup
CVE-2022-50701 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
0CVSS vectors
3Timeline events
0ADP providers
4Source links
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
CVE publishedCVE Program
The CVE record was published.
Dec 24, 2025, 10:55 UTC (UTC+00:00)
CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.