CVE-2026-43042

A flaw was found in the Linux kernel's Multiprotocol Label Switching (MPLS) module. This vulnerability is caused by a race condition where concurrent operations on network label data can lead to inconsistent memory access. This can result in out-of-bounds memory reads or writes, potentially causing system instability or a denial of service.

MPLS platform label updates lacked sequence protection; upstream adds seqcount for the label pair. Red Hat recommends patched kernels on MPLS edge routers; core MPLS may be built-in—patching remains primary.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, if MPLS functionality is not required, prevent the mpls_router kernel module from loading. This can be achieved by creating a modprobe configuration file.

1. Create a file /etc/modprobe.d/disable-mpls.conf with the following content:

   install mpls_router /bin/true
   

2. Rebuild the initramfs:

   dracut -f -v
   

3. Reboot the system for the changes to take effect.

Note that disabling the mpls_router module will prevent all MPLS routing functionality and may impact network operations if MPLS is in use.