CVE-2026-46273

/// Technical description

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

ibmveth: Disable GSO for packets with small MSS

Some physical adapters on Power systems do not support segmentation

offload when the MSS is less than 224 bytes. Attempting to send such

packets causes the adapter to freeze, stopping all traffic until

manually reset.

Implement ndo_features_check to disable GSO for packets with small MSS

values. The network stack will perform software segmentation instead.

The 224-byte minimum matches ibmvnic

commit <f10b09ef687f> ("ibmvnic: Enforce stronger sanity checks

on GSO packets")

which uses the same physical adapters in SEA configurations.

The issue occurs specifically when the hardware attempts to perform

segmentation (gso_segs > 1) with a small MSS. Single-segment GSO packets

(gso_segs == 1) do not trigger the problematic LSO code path and are

transmitted normally without segmentation.

Add an ndo_features_check callback to disable GSO when MSS < 224 bytes.

Also call vlan_

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References