CVE-2026-43042

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

mpls: add seqcount to protect the platform_label{,s} pair

The RCU-protected codepaths (mpls_forward, mpls_dump_routes) can have

an inconsistent view of platform_labels vs platform_label in case of a

concurrent resize (resize_platform_label_table, under

platform_mutex). This can lead to OOB accesses.

This patch adds a seqcount, so that we get a consistent snapshot.

Note that mpls_label_ok is also susceptible to this, so the check

against RTA_DST in rtm_to_route_config, done outside platform_mutex,

is not sufficient. This value gets passed to mpls_label_ok once more

in both mpls_route_add and mpls_route_del, so there is no issue, but

that additional check must not be removed.