Linux Kernel mt76 new_ctx null pointer dereference

Summaryinfo

A vulnerability has been found in Linux Kernel and classified as critical. Impacted is the function mt7921_channel_switch_rx_beacon/mt7925_channel_switch_rx_beacon of the component mt76. This manipulation of the argument new_ctx causes null pointer dereference. This vulnerability appears as CVE-2026-64325. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel (the affected version unknown). Affected by this vulnerability is the function mt7921_channel_switch_rx_beacon/mt7925_channel_switch_rx_beacon of the component mt76. The manipulation of the argument new_ctx with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. The summary by CVE is:

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

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-64325 since 07/19/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/25/2026).

Applying the patch 77e7b127472a191e086e1e0b1b051703f33b1801/351dd7d2c80d23e56dcce6faa4e62bea5b0877c7 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

License

• open-source

Website

• Vendor: https://www.kernel.org/

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