Oracle Linux: CVE-2019-12819: ELSA-2020-5708: Unbreakable Enterprise kernel security update (IMPORTANT) (Multiple Advisories)

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.
A use-after-free flaw was found in the Linux kernel's MDIO section of the network management subsystem. An attacker who is able to hot-plug a network device can trigger the __mdiobus_register() function in drivers/net/phy/mdio_bus.c, which can cause a use-after-free condition causing a memory corruption and kernel panic or privilege escalation.