Canonical Patches Intel Microcode Regression on Ubuntu PCs with Skylake CPUs

On November 12th, 2019, Canonical published important kernel security updates for all supported Ubuntu Linux releases to address two flaws (CVE-2019-11135 and CVE-2019-11139) discovered by various security researchers in Intel processors using Transactional Synchronization Extensions (TSX), as well as on certain Intel Xeon processors. While the first vulnerability could allow a local attacker to expose sensitive information, such as memory contents that were previously stored in microarchitectural buffers, the second issue could allow a local privileged attacker to cause a denial of service (system crash). The intel-microcode version that caused the regression was 3.20191112.