A flaw was found in the Linux kernel's memory deduplication mechanism. The max page sharing of Kernel Samepage Merging (KSM), added in Linux kernel version 4.4.0-96.119, can create a side channel. When the attacker and the victim share the same host and the default setting of KSM is "max page sharing=256", it is possible for the attacker to time the unmap to merge with the victim's page. The unmapping time depends on whether it merges with the victim's page and additional physical pages are created beyond the KSM's "max page share". Through these operations, the attacker can leak the victim's page.
{ "availability": "No subscription required", "ubuntu_priority": "low", "binaries": [ { "binary_version": "3.11.0-12.19", "binary_name": "block-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "block-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "crypto-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "crypto-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "fat-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "fat-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "fb-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "firewire-core-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "floppy-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "fs-core-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "fs-core-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "fs-secondary-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "fs-secondary-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "input-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "input-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "ipmi-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "ipmi-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "irda-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "irda-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "kernel-image-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "kernel-image-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-doc" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-headers-3.11.0-12" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-headers-3.11.0-12-generic" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-headers-3.11.0-12-generic-lpae" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-image-3.11.0-12-generic" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-image-3.11.0-12-generic-lpae" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-image-extra-3.11.0-12-generic" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-libc-dev" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-source-3.11.0" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-tools-3.11.0-12" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-tools-3.11.0-12-generic" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-tools-3.11.0-12-generic-lpae" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-tools-common" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-udebs-generic" }, { "binary_version": "3.11.0-12.19", "binary_name": "linux-udebs-generic-lpae" }, { "binary_version": "3.11.0-12.19", "binary_name": "md-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "md-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "message-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "mouse-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "mouse-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "multipath-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "multipath-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "nfs-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "nfs-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "nic-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "nic-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "nic-pcmcia-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "nic-shared-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "nic-shared-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "nic-usb-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "nic-usb-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "parport-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "parport-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "pata-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "pcmcia-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "pcmcia-storage-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "plip-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "plip-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "ppp-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "ppp-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "sata-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "sata-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "scsi-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "scsi-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "serial-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "speakup-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "speakup-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "squashfs-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "squashfs-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "storage-core-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "storage-core-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "usb-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "usb-modules-3.11.0-12-generic-lpae-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "virtio-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "vlan-modules-3.11.0-12-generic-di" }, { "binary_version": "3.11.0-12.19", "binary_name": "vlan-modules-3.11.0-12-generic-lpae-di" } ], "priority_reason": "Requires attacker preparing an exact match of a page from the victim in the first place." }
{ "availability": "No subscription required", "ubuntu_priority": "low", "binaries": [ { "binary_version": "5.15.0-1019.24~20.04.1.1", "binary_name": "linux-image-unsigned-5.15.0-1019-azure-fde" }, { "binary_version": "5.15.0-1019.24~20.04.1.1", "binary_name": "linux-image-unsigned-5.15.0-1019-azure-fde-dbgsym" } ], "priority_reason": "Requires attacker preparing an exact match of a page from the victim in the first place." }