Microsoft Security Response Center 中文 关注 CVE-2026-3842 Qemu-kvm: hyperv/syndbg: cpu_physical_memory_map 之后缺少映射长度保护，导致主机越界写入 CVE-2026-3842 Qemu-kvm: hyperv/syndbg: missing mapped-length guard after cpu_physical_memory_map causes host oob write msrc.microsoft.com
