Red Hat Security Advisory: kernel security and bug fix update

Important

The Linux kernel's TCP source port generation algorithm in the TCP stack contains a flaw due to the small table perturb size. This flaw allows an attacker to positively distinguish a system among devices with identical hardware and software, which lasts until the device restarts. An attacker can guess the evolution of the internal state used for source port generation. This information is used to infer the TCP traffic patterns of the victim, guessing the number of outgoing TCP connections established in a specific time frame, which can lead to a system fingerprinting.

CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor

A use-after-free flaw was found in the Linux kernel’s performance events functionality. A user triggers a race condition in setting up performance monitoring between the leading PERF_TYPE_TRACEPOINT and sub PERF_EVENT_HARDWARE plus the PERF_EVENT_SOFTWARE using the perf_event_open() function with these three types. This flaw allows a local user to crash the system.

CWE-366 - Race Condition within a Thread

[REJECTED CVE] A use-after-free vulnerability has been identified in the Linux Kernel's netfilter subsystem that did not properly handle the removal of stateful expressions in some situations. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code.

CWE-416 - Use After Free