Linux Kernel Vulnerability in MPLS Forwarding and Route Management

CVE-2026-43042

What is CVE-2026-43042?

A vulnerability has been identified in the Linux kernel related to the Multi-Protocol Label Switching (MPLS) functionality. The affected areas include the mpls_forward and mpls_dump_routes code paths, which may encounter an inconsistent view of platform labels during concurrent operations, specifically resizing the platform label table. When this occurs under the platform mutex, it can lead to out-of-bounds (OOB) accesses, compromising system integrity. A recent patch has introduced a seqcount to ensure a consistent snapshot of platform labels, preventing inconsistencies. Additionally, while checks against RTA_DST outside the platform mutex are not sufficient to eliminate potential vulnerabilities, this patch ensures that critical operations within mpls_route_add and mpls_route_del maintain integrity.

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