Sophos threat researcher Nick Gregory discovered a hole in Linux’s netfilter firewall program that’s “exploitable to achieve kernel code execution (via ROP [return-oriented programming]), giving full local privilege escalation, container escape, whatever you want.” ZDNet reports: Behind almost all Linux firewalls tools such as iptables; its newer version, nftables; firewalld; and ufw, is netfilter, which controls access to and from Linux’s network stack. It’s an essential Linux security program, so when a security hole is found in it, it’s a big deal. […] This problem exists because netfilter doesn’t handle its hardware offload feature correctly. A local, unprivileged attacker can use this to cause a denial-of-service (DoS), execute arbitrary code, and cause general mayhem. Adding insult to injury, this works even if the hardware being attacked doesn’t have offload functionality! That’s because, as Gregory wrote to a security list, “Despite being in code dealing with hardware offload, this is reachable