Live › vulnerability › CVE-2026-98796
Go to dashboardIn the Linux kernel's MediaTek Ethernet driver (mtk_eth_soc), the network interfaces could be brought up before the shared receive structures were created during probe, causing a kernel warning, a failed open, or a NULL dereference. The sources do not describe an attacker-controlled path, so the impact beyond a crash or failed interface is unknown.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Systems running a Linux kernel with the mtk_eth_soc MediaTek Ethernet driver, typically MediaTek-based routers and boards, where an interface is opened very early during boot. Systems without MediaTek Ethernet hardware are not affected.
No product ranges from the sources yet.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
In the Linux kernel, the following vulnerability has been resolved:
net: ethernet: mtk_eth_soc: allocate dummy netdev sooner
The RX rings and the shared NAPI are carried by an internal "dummy" netdev (eth->dummy_dev). mtk_probe() creates that dummy device, and adds the shared tx/rx NAPI to it, only after the MAC netdevs have been registered. That order has been there since the MT7623 support was added and leaves a window in which the netdevs are visible to the network core before the shared NAPI and the dummy device exist.
If anything brings the first netdev up during that window (e.g. netifd opening the WAN link the instant the interface is registered), the first-open path runs without them. On NETSYS v2 and later SoCs mtk_rx_alloc() -> __xdp_rxq_info_reg() then dereferences eth->dummy_dev == NULL:
WARNING: CPU: ... Missing net_device from driver
in net/core/xdp.c and mtk_open() fails with -ENODEV. On NETSYS v1 SoCs (MT7621/MT7622/MT7623/MT7629) there is no page pool, so the same open instead calls napi_enable() on a napi_struct that netif_napi_add() has not initialised yet and dereferences a NULL napi->dev.
Allocate the dummy netdev and add the shared tx/rx NAPI to it before the register_netdev() loop. Both the dummy-allocation failure and a register_netdev() failure now unwind through mtk_unreg_dev(), which unregisters the net_device notifiers and the netdevs registered so far, stopping a concurrently-opened netdev (ndo_stop) and its NAPI before the dummy carrier is freed.
A netdev that opened during the window can also have queued the frame-engine reset worker (via the tx watchdog or phylink), so the probe error path now cancels eth->pending_work before freeing the shared state, as mtk_cleanup() already does on remove.
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