Linux Kernel CVE-2026-31491

Apply the upstream kernel patch from commit e37afcb56ae070477741fe2d6e61fc0c542cce2d or upgrade to patched stable versions: Linux 6.18.21, 6.19.11, or 7.0 and later. For systems running 6.18, update to 6.18.21 or later in the 6.18 series; for 6.19 users, upgrade to 6.19.11 or later; for 7.0 pre-release systems, upgrade to final 7.0 release or later. If immediate kernel patching is not feasible, the primary compensating control is restricting RDMA device access to trusted applications and users via SELinux or AppArmor policies that limit irdma driver interaction, though this may impact legitimate RDMA workloads. Disable RDMA functionality entirely on systems where it is not required by blacklisting the irdma kernel module (add 'blacklist irdma' to /etc/modprobe.d/blacklist.conf and rebuild initramfs), though this permanently disables InfiniBand or RoCE (RDMA over Converged Ethernet) capabilities on affected hardware. System administrators should prioritize this patch during the next scheduled kernel update cycle, especially in high-performance computing and cloud data center environments where RDMA is actively used. References: https://git.kernel.org/stable/c/e37afcb56ae070477741fe2d6e61fc0c542cce2d