CVE-2026-43042 PUBLISHED

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

Assigner: Linux
Reserved: 01.05.2026 Published: 01.05.2026 Updated: 01.05.2026

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.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 7720c01f3f590116882e251f13c7e1d5602f8643 to 5bb3caf0bbfb56f1a00d2af072ac3d8395a3b9ef (excl.)
  • affected from 7720c01f3f590116882e251f13c7e1d5602f8643 to 629ec78ef8608d955ce217880cdc3e1873af3a15 (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 4.1 is affected
  • unaffected from 0 to 4.1 (excl.)
  • unaffected from 6.19.12 to 6.19.* (incl.)
  • unaffected from 7.0 to * (incl.)

References