Mitigating the 'Copy Fail' Vulnerability (CVE-2026-31431) with a Simple Ansible Playbook

postmaster@mlazzarotto.it (Marco Lazzarotto) — Fri, 01 May 2026 00:00:00 +0100

In a nutshell: there’s a new critical Linux bug going around

‘Copy Fail’ is a new and nasty local privilege escalation bug, CVE-2026-31431, discovered by the analyst team at Xint Code.

This bug essentially allows an attacker to gain root privileges on many Linux operating systems (Ubuntu, Debian, RHEL, Suse, Alma, Amazon Linux) using a Python script of just 732 bytes.

‘Copy Fail’ only requires a local unprivileged user account: no network access, no kernel debug capabilities, no pre-installed libraries. The kernel’s cryptographic API (AF_ALG) is enabled by default on virtually all major distributions, meaning the entire patch range from 2017 onward is vulnerable.

Ansible on Marco Lazzarotto

Mitigating the 'Copy Fail' Vulnerability (CVE-2026-31431) with a Simple Ansible Playbook

In a nutshell: there’s a new critical Linux bug going around