Oracle Linux: CVE-2020-12826: ELSA-2020-4060: kernel security, bug fix, and enhancement update (IMPORTANT) (Multiple Advisories)

A signal access-control issue was discovered in the Linux kernel before 5.6.5, aka CID-7395ea4e65c2. Because exec_id in include/linux/sched.h is only 32 bits, an integer overflow can interfere with a do_notify_parent protection mechanism. A child process can send an arbitrary signal to a parent process in a different security domain. Exploitation limitations include the amount of elapsed time before an integer overflow occurs, and the lack of scenarios where signals to a parent process present a substantial operational threat.
A flaw was found in the Linux kernel loose validation of child/parent process identification handling while filtering signal handlers. A local attacker is able to abuse this flaw to bypass checks to send any signal to a privileged process.