CVE-2024-27432

What it actually does

Failure to disable PPE scan mode prior to disabling the PPE in mtk_ppe_stop() leaves the engine in an active scanning state, causing a hang when the PPE is subsequently disabled during driver unload or system reboot.

Why it matters to the business

Devices using affected MediaTek Ethernet hardware may become unresponsive during planned restarts or maintenance windows, extending downtime and requiring physical or console intervention to recover.

How an attack unfolds

An attacker with the ability to trigger network interface teardown or initiate a reboot on a vulnerable system (via local access, administrative commands, or crafted network conditions that force PPE stop) can induce the hang condition described in the mtk_ppe_stop path.

How to fix it

Apply the upstream fix that disables PPE scan mode before PPE disable; update to Linux kernel commit 9fcadd125044007351905d40c405fadc2d3bb6d6 or later stable releases containing the patch. Reboot after update and verify PPE shutdown completes without hang.

How to confirm the fix worked

Confirm the presence of the scan-mode disable logic in mtk_ppe_stop() in the running kernel source or binary; perform controlled interface down and reboot tests while monitoring for PPE-related hangs or kernel traces.

Typical attack path

1. Obtain local or administrative access to trigger interface down or reboot sequence
2. Invoke mtk_ppe_stop() without prior scan-mode disable
3. Observe PPE hang preventing clean shutdown or causing system freeze

How to detect it

Review kernel logs and dmesg output around reboot or interface-down events for PPE-related hang messages or stalled shutdown traces; correlate with MediaTek Ethernet driver activity.

What your security team should do

• Prioritize patching kernel packages on all MediaTek Ethernet-equipped systems within maintenance windows
• Test reboot behavior on representative hardware after applying the fix
• Monitor vendor firmware updates that incorporate the referenced commit for embedded devices