CVE-2026-64325
Received Received - Intake

NULL Pointer Dereference in MediaTek mt76 WiFi Driver

Publication date: 2026-07-25

Last updated on: 2026-07-25

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7921/mt7925: fix NULL dereference in CSA beacon This patch is based on a BUG as reported by Bongani Hlope at https://lore.kernel.org/all/[email protected]/ When a channel-switch announcement (CSA) beacon is received, cfg80211 queues a wiphy work item that eventually calls mt7921_channel_switch_rx_beacon(). If the station disconnects (or the channel context is otherwise torn down) between the time the work is queued and the time it runs, the driver's dev->new_ctx pointer can already have been cleared to NULL. mt7921_channel_switch_rx_beacon() then dereferences new_ctx unconditionally, triggering a NULL pointer dereference at address 0x0: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:mt7921_channel_switch_rx_beacon+0x1f/0x100 [mt7921_common] The same missing guard exists in mt7925_channel_switch_rx_beacon(), which shares the same code pattern introduced by the same commit. Add an early-return NULL check for dev->new_ctx in both mt7921_channel_switch_rx_beacon() and mt7925_channel_switch_rx_beacon(). When new_ctx is NULL there is no pending channel switch to process, so returning immediately is the correct and safe action. Oops-Analysis: http://oops.fenrus.org/reports/lkml/[email protected]/report.html

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Meta Information

Published
2026-07-25
Last Modified
2026-07-25
Generated
2026-07-25
AI Q&A
2026-07-25
EPSS Evaluated
N/A
NVD
CVE-2026-64325
EUVD
EUVD-2026-48869

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux_kernel linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a NULL pointer dereference vulnerability in the Linux kernel's mt76 WiFi driver, specifically affecting the mt7921 and mt7925 chipsets. It occurs when a channel-switch announcement beacon is processed while the station is disconnecting or the channel context is torn down. The driver fails to check if a pointer is NULL before dereferencing it, causing a kernel crash at address 0x0.

Detection Guidance

This vulnerability is specific to the Linux kernel's mt76 driver for MediaTek Wi-Fi chips (mt7921/mt7925). Detection requires checking kernel logs for NULL pointer dereference errors related to mt7921_channel_switch_rx_beacon or mt7925_channel_switch_rx_beacon. Use: dmesg | grep -i 'NULL pointer dereference' or dmesg | grep -i 'mt7921_channel_switch_rx_beacon'.

Impact Analysis

If exploited, this vulnerability can crash the affected system by triggering a kernel panic. This leads to a denial of service, causing the system to reboot or become unresponsive. Systems using vulnerable mt7921 or mt7925 WiFi chipsets are at risk.

Mitigation Strategies

Apply the kernel patch that adds NULL checks for dev->new_ctx in mt7921_channel_switch_rx_beacon() and mt7925_channel_switch_rx_beacon(). Update to a patched kernel version. If immediate patching is not possible, disable affected Wi-Fi interfaces or restrict network access until the fix is applied.

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