Affected: Linux

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

eth: fbnic: Add validation for MTU changes

Increasing the MTU beyond the HDS threshold causes the hardware to fragment packets across multiple buffers. If a single-buffer XDP program is attached, the driver will drop all multi-frag frames. While we can't prevent a remote sender from sending non-TCP packets larger than the MTU, this will prevent users from inadvertently breaking new TCP streams.

Traditionally, drivers supported XDP with MTU less than 4Kb (packet per page). Fbnic currently prevents attaching XDP when MTU is too high. But it does not prevent increasing MTU after XDP is attached.