CopyFail: From Pod to Host

# Summary CVE-2026-31431 (Copy Fail) is a critical Linux kernel vulnerability that enables attackers to perform controlled 4-byte writes to the page cache of any readable file, allowing privilege escalation and container escape in Kubernetes environments. The exploit works by manipulating IPSec ESP Extended Sequence Number handling code to corrupt cached file contents without injecting kernel code, making it reliable and portable across systems. Two primary attack scenarios are possible: cross-container poisoning of co-located pods sharing image layers, and complete container escape to achieve root access on the host system.