Linux Kernel CVE-2026-31539

Update to patched kernel versions: 6.18.11 or later for 6.18.x series, 6.19.1 or later for 6.19.x series, or 7.0 for mainline tracking. Kernel source patches available at git.kernel.org commit references e811e60e1cc7 (6.18), f99996870222 (6.19), and 6e3c5052f968 (mainline). Organizations unable to patch immediately should disable SMB Direct RDMA transport by unloading the rdma kernel modules (modprobe -r smbdirect, ib_core) or configuring SMB clients/servers to use standard TCP transport instead, accepting the performance penalty - this completely eliminates exposure as the vulnerable code path is only active for RDMA connections. Firewall rules blocking RDMA ports (typically InfiniBand subnet manager on UDP 4789 or RoCE on configurable ports) provide network-level mitigation but may affect legitimate RDMA storage traffic. Monitor kernel logs for SMB Direct connection errors or credit exhaustion messages as potential exploitation indicators. Test RDMA functionality after mitigation as disabling can break storage connectivity in HPC or converged infrastructure environments.