Ubuntu Security Notice 3021-2 – Andrey Konovalov discovered that the CDC Network Control Model USB driver in the Linux kernel did not cancel work events queued if a later error occurred, resulting in a use-after-free. An attacker with physical access could use this to cause a denial of service (system crash). Kangjie Lu discovered an information leak in the core USB implementation in the Linux kernel. A local attacker could use this to obtain potentially sensitive information from kernel memory. Various other issues were also addressed.