CVE-2021-3489

The eBPF RINGBUF bpf_ringbuf_reserve() function in the Linux kernel did not
check that the allocated size was smaller than the ringbuf size, allowing
an attacker to perform out-of-bounds writes within the kernel and
therefore, arbitrary code execution. This issue was fixed via commit
4b81ccebaeee (“bpf, ringbuf: Deny reserve of buffers larger than ringbuf”)
(v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and
v5.10.37. It was introduced via 457f44363a88 (“bpf: Implement BPF ring
buffer and verifier support for it”) (v5.8-rc1).

Notes