CVE-2021-3679

Se encontró una falta de recursos de CPU en la funcionalidad tracing module del kernel de Linux en versiones anteriores a 5.14-rc3 en la manera en que el usuario usa el búfer de anillo de rastreo de una manera específica. Sólo usuarios locales privilegiados (con capacidad CAP_SYS_ADMIN) podían usar este fallo para privar de recursos causando una denegación de servicio

A lack of CPU resources in the Linux kernel tracing module functionality was found in the way users use the trace ring buffer in specific way. Only privileged local users (with CAP_SYS_ADMIN capability) could use this flaw to starve the resources causing denial of service.

It was discovered that the KVM hypervisor implementation in the Linux kernel did not properly perform reference counting in some situations, leading to a use-after-free vulnerability. An attacker who could start and control a VM could possibly use this to expose sensitive information or execute arbitrary code. It was discovered that the tracing subsystem in the Linux kernel did not properly keep track of per-cpu ring buffer state. A privileged attacker could use this to cause a denial of service. Various other issues were also addressed.