High Vulnerability in the Linux Kernel ("Copy Fail") (CERT-EU Security Advisory 2026-005)
On 29 April 2026, a high local privilege escalation vulnerability in the Linux kernel, tracked as CVE-2026-31431 and named "Copy Fail", was publicly disclosed.
The vulnerability affects every mainstream Linux distributions shipping a kernel built since 2017. A public proof-of-concept exploit has been released.
As of the date of this advisory, no distribution has shipped a fixed kernel package. The mainline fix was committed on 1 April 2026, but vendor updates are still pending across all major distributions.
CERT-EU strongly recommends applying the interim mitigation immediately, prioritising Kubernetes nodes, and CI/CD runners exposed to untrusted workloads.
https://www.cert.europa.eu/publications/security-advisories/2026-005/









