Live › vulnerability › CVE-2026-98798
Go to dashboardSetting Rx coalescing parameters with ethtool on a bcmgenet Ethernet interface that was never opened dereferences a NULL ring pointer, causing a kernel oops. The oops happens with RTNL held, so networking stays stuck until reboot.
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 Linux kernels with the Broadcom bcmgenet driver, such as Raspberry Pi CM4 and other GENET-based devices. The crash needs a local user or process able to run ethtool or send the netlink coalesce request against an interface that has not yet been brought up. Systems without bcmgenet hardware are not affected.
No product ranges from the sources yet.
Unknown from the sources.
Unknown from the sources.
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: bcmgenet: fix NULL dereference in set_coalesce before first open
The Rx ring priv and index are only set in bcmgenet_init_rx_ring(), which runs at open. Setting the Rx coalescing parameters on an interface that was never opened, e.g. "ethtool -C eth0 rx-usecs 50", dereferences a NULL ring->priv. The oops happens with RTNL held, so networking stays stuck until a reboot:
Unable to handle kernel paging request at virtual address 0000000000002788 pc : bcmgenet_set_rx_coalesce.isra.0+0x10/0x88 lr : bcmgenet_set_coalesce+0xe8/0x180 Call trace: bcmgenet_set_rx_coalesce.isra.0+0x10/0x88 (P) __ethnl_set_coalesce.isra.0+0x490/0x570 ethnl_set_coalesce+0x48/0xc0 ethnl_default_set_doit+0xf4/0x230 genl_family_rcv_msg_doit+0xe8/0x160 genl_rcv_msg+0x220/0x2a0 netlink_rcv_skb+0x68/0x140 genl_rcv+0x40/0x60 netlink_unicast+0x338/0x3c0 netlink_sendmsg+0x19c/0x3f8 __sock_sendmsg+0x64/0xc0 __sys_sendto+0x124/0x198 __arm64_sys_sendto+0x30/0x48
Set priv and index at probe. Writing the registers while the interface is down is harmless because open resets the MAC and bcmgenet_init_rx_coalesce() reapplies the stored values.
It was observed on a Raspberry Pi CM4, but should apply to all other genet devices.
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