CVE-2021-22555

En el archivo net/netfilter/x_tables.c se ha detectado una escritura fuera de límites en la pila que afecta a Linux desde la versión 2.6.19-rc1. Esto permite a un atacante alcanzar privilegios o causar una denegación de servicio (por medio de corrupción de la memoria de la pila) mediante el espacio de nombres de usuario

A flaw was discovered in processing setsockopt IPT_SO_SET_REPLACE (or IP6T_SO_SET_REPLACE) for 32 bit processes on 64 bit systems. This flaw will allow local user to gain privileges or cause a DoS through user name space. This action is usually restricted to root-privileged users but can also be leveraged if the kernel is compiled with CONFIG_USER_NS and CONFIG_NET_NS and the user is granted elevated privileges.

Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host’s physical memory. Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host's physical memory. Various other vulnerabilities were also addressed.