Linux Kernel DLM CVE-2026-43125

Upgrade to patched kernel versions: 6.12.75, 6.18.16, 6.19.6, or 7.0 or later, depending on your distribution's kernel branch. Distribution-specific updates should be applied through standard package management (yum/dnf for RHEL/CentOS, apt for Debian/Ubuntu, zypper for SUSE). Kernel updates require system reboot to take effect. Patch commit references are available at https://git.kernel.org/stable/c/67288113c5e6cf9e659b4065c0ed6f16100e0c71 and related stable branch commits. For systems where immediate patching is not feasible, implement compensating controls: disable the DLM kernel module (modprobe -r dlm) if clustering functionality is not required, though this will break clustered filesystem operations; restrict network access to DLM ports (TCP 21064 default) using firewall rules to allow only trusted cluster node IP addresses, which reduces attack surface but does not eliminate risk from compromised cluster members; isolate cluster management networks on dedicated VLANs without internet connectivity. Note that disabling DLM will cause clustered filesystems to fail and should only be done on non-clustered systems. Network isolation is the most practical temporary mitigation for production clusters pending maintenance windows.