A severe security vulnerability affecting almost every version of the Linux operating system has caught defenders off-guard and scrambling to patch after security researchers publicly released exploit code that allows attackers to take complete control of vulnerable systems. The U.S. government says the bug, dubbed “CopyFail,” is now being exploited in the wild , meaning it’s being actively used in malicious hacking campaigns. The bug, officially tracked as CVE-2026-31431 and discovered in Linux kernel versions 7.0 and earlier, was disclosed to the Linux kernel security team in late March, and patched after about a week. But the patches have yet to fully trickle down to the many Linux distributions that rely on the vulnerable kernel, leaving any system running an affected Linux version at risk of compromise.…