Ubuntu Security Notice USN-3756-1

Ubuntu Security Notice 3756-1 - It was discovered that memory present in the L1 data cache of an Intel CPU core may be exposed to a malicious process that is executing on the CPU core. This vulnerability is also known as L1 Terminal Fault. A local attacker in a guest virtual machine could use this to expose sensitive information. Jann Horn and Ken Johnson discovered that microprocessors utilizing speculative execution of a memory read may allow unauthorized memory reads via a sidechannel attack. This flaw is known as Spectre Variant 4. A local attacker could use this to expose sensitive information, including kernel memory. Various other issues were also addressed.