Security update for the Linux Kernel

The SUSE Linux Enterprise 15 SP3 RT kernel was updated to receive various security bugfixes. The following security bugs were fixed: - CVE-2025-38234: sched/rt: Fix race in push_rt_task (bsc#1246057). - CVE-2026-23103: ipvlan: Make the addrs_lock be per port (bsc#1257773). - CVE-2026-23243: RDMA/umad: Reject negative data_len in ib_umad_write (bsc#1259797). - CVE-2026-23272: netfilter: nf_tables: unconditionally bump set->nelems before insertion (bsc#1260009). - CVE-2026-23274: netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels (bsc#1260005). - CVE-2026-23293: net: vxlan: fix nd_tbl NULL dereference when IPv6 is disabled (bsc#1260486). - CVE-2026-23398: icmp: fix NULL pointer dereference in icmp_tag_validation() (bsc#1260730).