CVE-2026-98929

In the Linux kernel, the following vulnerability has been resolved:

macsec: initialize SecY before registering the netdevice

Creating a MACsec device with MAC offload over an LRO-capable lower device triggers a warning in rtmsg ifinfo build skb() when IPv4 forwarding is enabled by default.

register netdevice() invokes inetdev init(), which disables LRO and emits a NETDEV FEAT CHANGE notification. This reaches macsec fill info() before macsec add dev() initializes the SecY. key len is still zero, so macsec fill info() returns -EMSGSIZE and trips the WARN ON in rtmsg ifinfo build skb(), even though the skb has enough space.

Even without the warning, notifications during registration can report uninitialized SecY attributes, including the SCI. This ordering has existed since the driver was introduced.

Initialize the SecY and apply the new-link attributes before registration. Move MAC address inheritance into macsec newlink() so the SCI can also be initialized before registration-time notifications report it. Move the per-CPU statistics and metadata destination allocation into ndo init(), and release partial allocations on failure.