Oracle Linux: CVE-2020-27171: ELSA-2021-9223: Unbreakable Enterprise kernel-container security update (IMPORTANT) (Multiple Advisories)

An issue was discovered in the Linux kernel before 5.11.8. kernel/bpf/verifier.c has an off-by-one error (with a resultant integer underflow) affecting out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory, aka CID-10d2bb2e6b1d.
A flaw was found in the Linux kernels eBPF verification code. By default accessing the eBPF verifier is only accessible to privileged users with CAP_SYS_ADMIN. A flaw that triggers Integer underflow when restricting speculative pointer arithmetic allows unprivileged local users to leak the content of kernel memory. The highest threat from this vulnerability is to data confidentiality.