Together AI: Mitigating the Copy Fail Linux Kernel Vulnerability in Production GPU Infrastructure

Together AI Blog·medium signal

Together AI published a technical deep-dive on how they shut down exposure to CVE-2026-31431 ('Copy Fail'), the unpatched Linux kernel local privilege escalation and container escape vulnerability that allows writing four controlled bytes into any readable file's page cache. The post details their production response across GPU clusters where no mainline patch exists yet — relevant to anyone running AI inference or training workloads on Linux. The Register confirmed the flaw on April 30.