How Cloudflare responded to the “Copy Fail” Linux vulnerability

On April 29, 2026, a Linux kernel local privilege escalation vulnerability was publicly disclosed under the name “Copy Fail” (CVE-2026-31431). Cloudflare’s Security and Engineering teams began assessing the vulnerability as soon as it was disclosed. We reviewed the exploit technique, evaluated exposure across our infrastructure, and validated that our existing behavioral detections could identify the exploit pattern within minutes. There was no impact to the Cloudflare environment, no customer data was at risk, and no services were disrupted at any point.