Bug 1780586 (CVE-2019-0162, Spoiler)

The SPOILER vulnerability is a micro-architectural leakage which allows an attacker to determine virtual-to-physical page mappings in unprivileged user space processes. It leverages data dependency of speculative load and store operations in the Memory Order Buffer and uses rdtscp and mfence instructions to measure the timing discrepancies that reveal memory layout. This allows to detect ranges of contiguous physical memory pages which makes RowHammer much more effective and easier, just seconds of an attack instead of weeks.