CVE-2024-50045

/// Technical description

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

netfilter: br_netfilter: fix panic with metadata_dst skb

Fix a kernel panic in the br_netfilter module when sending untagged

traffic via a VxLAN device.

This happens during the check for fragmentation in br_nf_dev_queue_xmit.

It is dependent on:

1) the br_netfilter module being loaded;

2) net.bridge.bridge-nf-call-iptables set to 1;

3) a bridge with a VxLAN (single-vxlan-device) netdevice as a bridge port;

4) untagged frames with size higher than the VxLAN MTU forwarded/flooded

When forwarding the untagged packet to the VxLAN bridge port, before

the netfilter hooks are called, br_handle_egress_vlan_tunnel is called and

changes the skb_dst to the tunnel dst. The tunnel_dst is a metadata type

of dst, i.e., skb_valid_dst(skb) is false, and metadata->dst.dev is NULL.

Then in the br_netfilter hooks, in br_nf_dev_queue_xmit, there's a check

for frames that needs to be fragmented: frames with higher MTU than the

VxLAN de

/// 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