It was discovered that the eBPF implementation in the Linux kernel did
not properly track bounds information for 32 bit registers when
performing div and mod operations. A local attacker could use this to
possibly execute arbitrary code.

It was discovered that the eBPF implementation in the Linux kernel did not
properly track bounds information for 32 bit registers when performing div
and mod operations. A local attacker could use this to possibly execute
arbitrary code.

sbeattie	4.15 kernels the only ubuntu kernels that have not yet had the fix applied for 4.15 kernels, f6b1b3bf0d5f ("bpf: fix subprog verifier bypass by div/mod by 0 exception") is needed as a prerequisite but introduces CVE-2021-3444
cascardo	Commit f1174f77b50c is also necessary to exploit, and is not present on 4.4 kernels.