An issue was discovered in the Linux kernel before 5.0. The function __mdiobus_register() in drivers/net/phy/mdio_bus.c calls put_device(), which will trigger a fixed_mdio_bus_init use-after-free. This will cause a denial of service. CREATE(Triage): {Link=https://nvd.nist.gov/vuln/detail/CVE-2019-12819 User=admin}