A flaw was found in the Linux kernel. Measuring usage of the shared memory does not scale with large shared memory segment counts which could lead to resource exhaustion and DoS.

A flaw was found in the way KVM hypervisor handled x2APIC Machine Specific Rregister(MSR) access with nested(=1) virtualization enabled. In that, L1 guest could access L0's APIC register values via L2 guest, when 'virtualize x2APIC mode' is enabled.

A guest could use this flaw to potentially crash the host kernel resulting in DoS issue.

Upstream patches: ----------------- -> https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=acff78477b9b4f26ecdf65733a4ed77fe837e9dc -> https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=c73f4c998e1fd4249b9edfa39e23f4fda2b9b041

Reference: ---------- -> https://www.openwall.com/lists/oss-security/2019/04/08/1

An information leakage issue was found in the way Linux kernel's KVM hypervisor handled page fault exception while emulating instructions like VMXON, VMCLEAR, VMPTRLD, VMWRITE with memory address as an operand. It occurs if the operand is an mmio address, as the returned exception object holds uninitialised stack memory contents.

A guest user/process could use this flaw to leak host's stack memory contents to a guest.

It affects only Intel processors and only when nested virtualization is enabled.

Upstream patch: --------------- -> https://git.kernel.org/linus/353c0956a618a07ba4bbe7ad00ff29fe70e8412a

Reference: ---------- -> https://www.openwall.com/lists/oss-security/2019/02/18/2

A flaw was found in the Linux kernel's implementation of logical link control and adaptation protocol (L2CAP), part of the Bluetooth stack in the l2capparseconfrsp and l2capparseconfreq functions. An attacker with physical access within the range of standard Bluetooth transmission can create a specially crafted packet. The response to this specially crafted packet can contain part of the kernel stack which can be used in a further attack.

A flaw was found in the Linux kernel's implementation of Logical Link Control and Adaptation Protocol (L2CAP), part of the Bluetooth stack. An attacker, within the range of standard Bluetooth transmissions, can create and send a specially crafted packet. The response to this specially crafted packet can contain part of the kernel stack which can be used in a further attack.