Affected: The Linux Foundation kernel

A flaw was found in the Linux kernel's handle_rx() function in the [vhost_net] driver. A malicious virtual guest, under specific conditions, can trigger an out-of-bounds write in a kmalloc-8 slab on a virtual host which may lead to a kernel memory corruption and a system panic. Due to the nature of the flaw, privilege escalation cannot be fully ruled out. Versions from v4.16 and newer are vulnerable.

Affected: Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-hwe

USN-3903-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.10. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.10 for Ubuntu 18.04 LTS.

Jason Wang discovered that the vhost net driver in the Linux kernel contained an out of bounds write vulnerability. An attacker in a guest virtual machine could use this to cause a denial of service (host system crash) or possibly execute arbitrary code in the host kernel. (CVE-2018-16880)

Jann Horn discovered that the userfaultd implementation in the Linux kernel did not properly restrict access to certain ioctls. A local attacker could use this possibly to modify files. (CVE-2018-18397)

Jann Horn discovered a race condition in the fork() system call in the Linux kernel. A local attacker could use this to gain access to services that cache authorizations. (CVE-2019-6133)